8/28/25 – NOAA’s Southern Climate Impacts Planning Program (SCIPP) just published its annual report. It includes new research findings on three key elements of tropical systems: a lengthening tropical season, stalling storms, and tropical cyclone size at landfall.
SCIPP publishes fascinating reports tailored to the south central region of the U.S. including Texas, Oklahoma and Louisiana.
The government/university partnership conducts research to understand climate hazard trends and patterns that are useful to decision makers. The information below is summarized from their annual report.
Tropical Season Lengthens 16 days
SCIPP analysis of Atlantic hurricane season length from 1970 to 2022 found that storms are forming increasingly earlier AND later in the season. In 1970, the first named storm formed around July 27th. However, by 2022, the date shifted to around May 31st. That represents an increase of season length of 11 days per decade … just on the front end.
On the back end, in 1970, the last named storm dissipated around October 24th. However, in 2022, the last storm dissipated around November 18th. This represents a roughly 5-day per decade shift, say the researchers.
“While improvements in observational practices raised some concerns about data quality,” they say, “our results suggest that the primary driver of season expansion is the earlier onset and prolonged persistence of favorable conditions for tropical cyclones, such as warm sea surface temperatures, elevated humidity, and reduced wind shear.”
The researchers recommend that the National Hurricane Center consider moving the start of hurricane season to May 15th to heighten awareness of these early season storms. They have presented their work widely within the scientific community. For more information, see Dr. Vincent Brown’s virtual presentation to the Inland Marine Underwriters Association.
Stalling Storms Increasing 1.5% Per Year
SCIPP researchers also found seasonality in stalling storms. Stalling is most common in October (17.3% of storms) and least common in August (8.2%).
Their analysis showed a significant increase in annual stalling frequency during the satellite era (1966–2020) at 1.5% per year.
They also found an increase in the proportion of stalling storms relative to all storms.
SCIPP 2024-2025 Annual Report
Stalling storms were also significantly more likely to reach major-hurricane intensity.
These findings have been presented to stakeholders, academic audiences, and emergency managers to help them better prepare for future stalling events in vulnerable regions.
“Size at Landfall” Increasing Later in Season
The third featured project was a database of tropical cyclone size at landfall.
Size at landfall is critical in determining the extent and severity of storm impacts.
SCIPP 2024-2025 Annual Report
Accurate size data allows emergency managers, planners, and policymakers to better estimate potential exposure, improve evacuation planning, allocate resources, and design infrastructure that accounts for the full spatial footprint of storms. Their database supports:
Enhanced risk assessments
Insurance modeling
Building codes
Long-term coastal planning.
The analysis found no statistically significant long-term change in size at landfall, However, it did find that:
Parts of the season—particularly September through November—exhibited larger landfall sizes compared to other months.
Average landfall size was comparable between the Gulf of Mexico and the East Coast.
Size did not differ significantly across Category 1–4 storms.
Implications of the Three Studies
SCIPP says that collectively, these three studies highlight the “critical need to better understand tropical cyclone characteristics that directly affect coastal populations.”
The researchers hope to translate their scientific findings into actionable guidance for emergency management, infrastructure planning, and long-term community resilience.
The annual report also contains fascinating findings by leading academic institutions in the region on:
Hazard mitigation in areas without hazard mitigation planning capabilities
Heat stress and football-game kickoff times
Impacts of fiscal decentralization on Disaster Risk Reduction
Climate migration
Case studies
Workshop and intern opportunities
More
SCIPP’s theme is “Planning for Long-Term Change in a Short-Term World.” To learn more about their excellent work and conferences, or to sign up for their newsletters, visit SouthernClimate.org.
Posted by Bob Rehak on 8/28/2025
2921 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2021/05/TS-Harvey-8-30-17-209.jpg?fit=1024%2C768&ssl=17681024adminadmin2025-08-28 19:29:022025-08-28 19:41:24SCIPP Research Sheds New Light on Key Elements of Tropical Systems
8/27/2025 – This week marks the 8th anniversary of Hurricane Harvey and the 20th anniversary of Hurricane Katrina – two of the most destructive storms in recent American history. So I wanted to see what the hurricane stats tell us about this part of the hurricane season as far back as we can reliably see.
The National Hurricane Center has an excellent climatology page for the broader Atlantic basin. But I could not find any lists on their site for the Gulf and Texas. So I asked ChatGPT for some research help narrowing the geographic scope. Here’s what it found in the data.
Notable Late August Major Hurricanes to Strike Gulf Coast
Several major hurricanes have struck the U.S. Gulf Coast in late August (roughly August 20–31) over the years. Here are the most notable ones:
1. Hurricane Katrina (2005)
Dates: August 23 – 30, 2005
Landfall: August 29 in southeast Louisiana and Mississippi
Impact: One of the costliest and deadliest U.S. hurricanes; catastrophic flooding in New Orleans after levee failures.
2. Hurricane Laura (2020)
Dates: August 20 – 29, 2020
Landfall: August 27 near Cameron, Louisiana (Category 4, 150 mph winds)
Impact: Devastated southwest Louisiana, massive storm surge and wind destruction.
3. Hurricane Harvey (2017)
Dates: August 17 – September 2, 2017
Landfall: August 25 near Rockport, Texas (Category 4)
Impact: Record-breaking rainfall in Houston region (up to 60″), catastrophic flooding across southeast Texas.
4. Hurricane Isaac (2012)
Dates: August 21 – September 1, 2012
Landfall: August 28 in southeast Louisiana (Category 1)
Impact: Widespread flooding, long-duration storm surge, power outages.
5. Hurricane Gustav (2008)
Dates: August 25 – September 4, 2008
Landfall: September 1 in Louisiana (Category 2), but struck the Gulf Coast region late August while strengthening.
6. Hurricane Andrew (1992)
Dates: August 16 – 28, 1992
Landfall: August 24 in South Florida, then August 26 in Louisiana (Category 3)
Impact: One of the most destructive U.S. hurricanes prior to Katrina.
Hurricane Camille (1969): Landfall August 17 (slightly before “late August,” but historic impact on Mississippi).
Hurricane Allen (1980): Active early to mid-August, not late August.
1999 Bret — Aug 22 • TX • Cat 3.
Hurricane Ida (2021): Formed August 26, made landfall August 29 in Louisiana as Category 4.
✅ Pattern: Late August is part of the peak hurricane season in the Gulf; multiple historic storms—including Katrina, Harvey, Laura, and Ida—all struck between August 25–29.
Two Thirds of All Gulf Coast Hurricanes Strike in August and September
Next, I asked ChatGPT to graph the distribution of all hurricanes (not just majors) to strike the Gulf Coast by month since 1851. NOAA last updated this information in 2020. So, these numbers do not include the last 5 years.
The total was 212; 141 in August and September. That works out to 66.5% of the total.
Counts by month (1851–2020) of all Gulf Coast Hurricanes:
June: 9
July: 17
August: 58
September: 83
October: 39
November: 6
👉 The peak is September, followed by August, then a secondary bump in October. Early (June–July) and late (November) landfalls are much rarer.
Texas Shows Even More Pronounced Concentration in August/September
By contrast, seventy-one percent of all Texas Hurricanes happen in August and September, a slightly higher concentration. We also get proportionately fewer in October compared to the entire Gulf.
Texas hurricane landfalls by month from 1851-2020 include:
June: 5
July: 7
August: 25
September: 29
October: 9
November: 1
Pattern of Active Decades
The distribution suggests clusters of active decades rather than a steady increase or decrease.
List of Texas Hurricane Landfalls
Here’s a historical list of Texas hurricane landfalls (1851–2020), drawn from NOAA’s official Hurricane Research Division dataset. I’ve grouped them by month and included year, name (if available), and Saffir–Simpson category.
June (5 total)
1871 – Indianola hurricane (Cat 3)
1886 – Indianola hurricane (Cat 4, destroyed the city)
1934 – June hurricane (Cat 2)
1957 – Audrey (Cat 3, TX/LA border, strongest in LA but impacted TX)
1960 – Unnamed June storm (Cat 1)
Beryl last year would be a notable addition to this list if we expanded the range of years.
July (7 total)
1867 – Unnamed hurricane (Cat 3, Galveston)
1888 – Unnamed hurricane (Cat 2, TX/LA border)
1909 – July hurricane (Cat 3, Port Arthur region)
1916 – July hurricane (Cat 3, Baffin Bay region)
1933 – July hurricane (Cat 3, south Texas)
1943 – July hurricane (Cat 1, Galveston/Houston area)
1970 – Celia (Cat 3, Corpus Christi, devastating wind damage)
August (25 total)
1880 – Indianola hurricane (Cat 2)
1915 – Galveston hurricane (Cat 4)
1932 – Freeport hurricane (Cat 4)
1942 – August hurricane (Cat 3, near Port O’Connor)
1945 – Texas hurricane (Cat 3, Matagorda)
1947 – Hurricane #4 (Cat 1, Brownsville region)
1961 – Carla (Cat 4, Matagorda)
1967 – Beulah (Cat 3, Brownsville)
1980 – Allen (Cat 3, near Brownsville)
1983 – Alicia (Cat 3, Galveston/Houston)
1999 – Bret (Cat 3, Padre Island, sparsely populated region)
2005 – Rita (Cat 3, TX/LA border, strongest impacts in LA but landfall partly in TX)
2008 – Dolly (Cat 1, near Brownsville)
2008 – Ike (Cat 2, Galveston/Houston, catastrophic surge)
2017 – Harvey (Cat 4, Rockport/Port Aransas, record flooding in Houston area) (and numerous weaker Cat 1–2 storms in between)
September (29 total)
1900 – Galveston hurricane (Cat 4, deadliest natural disaster in U.S. history)
1919 – Florida Keys / Corpus Christi hurricane (Cat 4, catastrophic in Corpus Christi)
1933 – September hurricane (Cat 3, Brownsville)
1967 – Beulah (still active early September after Aug landfall)
2002 – Lili (weaker in TX, major in LA)
2020 – Hanna (Cat 1, South Padre region) (plus ~20 others Cat 1–3 from NOAA HRD record, mostly South Texas landfalls)
1912 – October hurricane (Cat 2, Gulf coast TX/LA border)
1949 – October hurricane (Cat 2, Freeport area)
1989 – Jerry (Cat 1, near Galveston)
November (1 total)
1980 – Hurricane Jeanne (Cat 1, weakened quickly at landfall in south Texas)
✅ Key Pattern:
Peak months for Texas hurricane landfalls are August & September
The most destructive TX hurricanes historically include:
1900 Galveston (Cat 4)
1915 Galveston (Cat 4)
1919 Corpus Christi (Cat 4)
1961 Carla (Cat 4)
1983 Alicia (Cat 3)
2008 Ike (Cat 2, massive surge)
2017 Harvey (Cat 4, catastrophic flooding)
1900 Galveston Hurricane Still Deadliest Ever
The 1900 Galveston Hurricane (September 8, 1900) remains the deadliest natural disaster in U.S. history. Estimated deaths range from 6,000 to 12,000. But the most widely cited figure is 8,000. Roughly one-third of Galveston’s population perished, thousands of homes were destroyed, and the disaster reshaped how the U.S. approached hurricane forecasting and preparedness.
By contrast, Hurricane Harvey in 2017 killed 68 people statewide and 36 in Harris County. You can attribute the improvement (reduction) to better forecasting and infrastructure.
Posted by Bob Rehak on 8/27/2025with research assistance from ChatGPT
2920 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2025/08/3_texas_monthly_counts.png?fit=1800%2C1000&ssl=110001800adminadmin2025-08-27 18:46:132025-08-27 18:47:31Hurricane Stats for Gulf Coast and Texas Going Back to 1850
Montgomery County has finally updated its drainage criteria manual…eight years after Hurricane Harvey caused widespread flooding that exposed shortcomings in its previous manual which dated to the 1980s.
Unanimously Approved
MoCo Commissioners approved the new manual unanimously this morning. The draft of the new manual was first proposed in early 2024. That followed a minor update in 2019 from the county’s old 1988 drainage criteria manual in effect at the time of Harvey.
The new manual does not adopt all of the minimum drainage recommendations proposed by Harris County for areas draining into Harris, though it is a vast improvement over the previous iteration.
Minimum Drainage Requirements Proposed by Harris County
1. Using Atlas 14 rainfall rates for sizing storm water conveyance and detention systems. 2. Requiring a minimum detention rate of 0.55 acre-feet per acre of detention for any new development on tracts one acre or larger. A single-family residential structure and accessory building proposed on an existing lot is exempt from providing detention. 3. Prohibiting the use of hydrograph timing as a substitute for detention on any project, unless it directly outfalls into Galveston Bay. 4. Requiring “no net fill” in the current mapped 500-year floodplain, except in areas identified as coastal zones only. 5. Requiring the minimum Finished Flood Elevation of new habitable structures be established at or waterproofed to the 500-year flood elevation as shown on the effective Flood Insurance Study.
Major Changes in New MoCo Drainage Criteria Manual
MoCo’s new drainage criteria manual includes some, but not all, of those recommendations.
Comparison of Recommendations
Measure
Harris
Montgomery
Use of Atlas 14 Rainfall Standards
Yes
Yes
Minimum Detention Rate
.55 acre feet/acre
.55 acre feet/acre for areas greater than 20 acres (see page 57)
Prohibit Hydrographic Timing
Yes
Yes, but with limitations (see page 68)
No Net Fill in 500-Yr Floodplain
Prohibited
Still allowed
Finished Floor Elevation
At 500-yr flood elevation
Requires drainage be maintained one foot below lowest finished floor elevation for 100-year event (See page 54)
It’s not perfect. But it’s a vast improvement. Assuming the county enforces them.
Montgomery County resident Chad Price addressed Commissioners Court before the vote. He applauded most of the updates in the manual. However, he also urged commissioners to adopt ALL of Harris County’s minimum requirements.
Price emphasized the uncertainty surrounding rainfall rates, the increasing frequency of storms that exceed predicted maximums, and flood maps that have yet to be updated to reflect Atlas-14.
He made two excellent points:
We must not design drainage systems based on outdated data.
Better flood regulations are not about stopping growth—they’re about making sure growth is sustainable and safe.
In that regard, Price urged commissioners to update building codes, require smarter drainage planning, preserve natural floodplains, and use science-based floodplain mapping. He said, “These steps will reduce long-term costs to taxpayers, protect property values, and most importantly, safeguard our communities.”
Next Up
Montgomery County’s Floodplain Manager currently shows floodplain regulations adopted in 2014. That’s before the Tax Day, Memorial Day, Harvey, Imelda and May Day 2024 floods. Given the thousands of homes in MoCo that flood repeatedly, there may be some opportunities for improvement in those floodplain regs.
Posted by Bob Rehak on 8/26/25
2919 Days since Hurricane Harvey
The thoughts expressed in this post represent opinions on matters of public concern and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2025/08/20250826-MoCo-DCM-Cover.jpg?fit=1100%2C710&ssl=17101100adminadmin2025-08-26 16:41:062025-08-26 17:26:10MoCo Adopts New Drainage Criteria Manual 8 Years After Harvey
SCIPP Research Sheds New Light on Key Elements of Tropical Systems
8/28/25 – NOAA’s Southern Climate Impacts Planning Program (SCIPP) just published its annual report. It includes new research findings on three key elements of tropical systems: a lengthening tropical season, stalling storms, and tropical cyclone size at landfall.
SCIPP publishes fascinating reports tailored to the south central region of the U.S. including Texas, Oklahoma and Louisiana.
The government/university partnership conducts research to understand climate hazard trends and patterns that are useful to decision makers. The information below is summarized from their annual report.
Tropical Season Lengthens 16 days
SCIPP analysis of Atlantic hurricane season length from 1970 to 2022 found that storms are forming increasingly earlier AND later in the season. In 1970, the first named storm formed around July 27th. However, by 2022, the date shifted to around May 31st. That represents an increase of season length of 11 days per decade … just on the front end.
On the back end, in 1970, the last named storm dissipated around October 24th. However, in 2022, the last storm dissipated around November 18th. This represents a roughly 5-day per decade shift, say the researchers.
“While improvements in observational practices raised some concerns about data quality,” they say, “our results suggest that the primary driver of season expansion is the earlier onset and prolonged persistence of favorable conditions for tropical cyclones, such as warm sea surface temperatures, elevated humidity, and reduced wind shear.”
The researchers recommend that the National Hurricane Center consider moving the start of hurricane season to May 15th to heighten awareness of these early season storms. They have presented their work widely within the scientific community. For more information, see Dr. Vincent Brown’s virtual presentation to the Inland Marine Underwriters Association.
Stalling Storms Increasing 1.5% Per Year
SCIPP researchers also found seasonality in stalling storms. Stalling is most common in October (17.3% of storms) and least common in August (8.2%).
Their analysis showed a significant increase in annual stalling frequency during the satellite era (1966–2020) at 1.5% per year.
Stalling storms were also significantly more likely to reach major-hurricane intensity.
These findings have been presented to stakeholders, academic audiences, and emergency managers to help them better prepare for future stalling events in vulnerable regions.
“Size at Landfall” Increasing Later in Season
The third featured project was a database of tropical cyclone size at landfall.
Accurate size data allows emergency managers, planners, and policymakers to better estimate potential exposure, improve evacuation planning, allocate resources, and design infrastructure that accounts for the full spatial footprint of storms. Their database supports:
The analysis found no statistically significant long-term change in size at landfall, However, it did find that:
Implications of the Three Studies
SCIPP says that collectively, these three studies highlight the “critical need to better understand tropical cyclone characteristics that directly affect coastal populations.”
The researchers hope to translate their scientific findings into actionable guidance for emergency management, infrastructure planning, and long-term community resilience.
The annual report also contains fascinating findings by leading academic institutions in the region on:
SCIPP’s theme is “Planning for Long-Term Change in a Short-Term World.” To learn more about their excellent work and conferences, or to sign up for their newsletters, visit SouthernClimate.org.
Posted by Bob Rehak on 8/28/2025
2921 Days since Hurricane Harvey
Hurricane Stats for Gulf Coast and Texas Going Back to 1850
8/27/2025 – This week marks the 8th anniversary of Hurricane Harvey and the 20th anniversary of Hurricane Katrina – two of the most destructive storms in recent American history. So I wanted to see what the hurricane stats tell us about this part of the hurricane season as far back as we can reliably see.
The National Hurricane Center has an excellent climatology page for the broader Atlantic basin. But I could not find any lists on their site for the Gulf and Texas. So I asked ChatGPT for some research help narrowing the geographic scope. Here’s what it found in the data.
Notable Late August Major Hurricanes to Strike Gulf Coast
Several major hurricanes have struck the U.S. Gulf Coast in late August (roughly August 20–31) over the years. Here are the most notable ones:
1. Hurricane Katrina (2005)
2. Hurricane Laura (2020)
3. Hurricane Harvey (2017)
4. Hurricane Isaac (2012)
5. Hurricane Gustav (2008)
6. Hurricane Andrew (1992)
Other Notable Late-August Gulf Hurricanes
✅ Pattern: Late August is part of the peak hurricane season in the Gulf; multiple historic storms—including Katrina, Harvey, Laura, and Ida—all struck between August 25–29.
Two Thirds of All Gulf Coast Hurricanes Strike in August and September
Next, I asked ChatGPT to graph the distribution of all hurricanes (not just majors) to strike the Gulf Coast by month since 1851. NOAA last updated this information in 2020. So, these numbers do not include the last 5 years.
The total was 212; 141 in August and September. That works out to 66.5% of the total.
Counts by month (1851–2020) of all Gulf Coast Hurricanes:
👉 The peak is September, followed by August, then a secondary bump in October. Early (June–July) and late (November) landfalls are much rarer.
Texas Shows Even More Pronounced Concentration in August/September
By contrast, seventy-one percent of all Texas Hurricanes happen in August and September, a slightly higher concentration. We also get proportionately fewer in October compared to the entire Gulf.
Texas hurricane landfalls by month from 1851-2020 include:
Pattern of Active Decades
The distribution suggests clusters of active decades rather than a steady increase or decrease.
List of Texas Hurricane Landfalls
Here’s a historical list of Texas hurricane landfalls (1851–2020), drawn from NOAA’s official Hurricane Research Division dataset. I’ve grouped them by month and included year, name (if available), and Saffir–Simpson category.
June (5 total)
Beryl last year would be a notable addition to this list if we expanded the range of years.
July (7 total)
August (25 total)
(and numerous weaker Cat 1–2 storms in between)
September (29 total)
(plus ~20 others Cat 1–3 from NOAA HRD record, mostly South Texas landfalls)
October (9 total)
November (1 total)
✅ Key Pattern:
1900 Galveston Hurricane Still Deadliest Ever
The 1900 Galveston Hurricane (September 8, 1900) remains the deadliest natural disaster in U.S. history. Estimated deaths range from 6,000 to 12,000. But the most widely cited figure is 8,000. Roughly one-third of Galveston’s population perished, thousands of homes were destroyed, and the disaster reshaped how the U.S. approached hurricane forecasting and preparedness.
By contrast, Hurricane Harvey in 2017 killed 68 people statewide and 36 in Harris County. You can attribute the improvement (reduction) to better forecasting and infrastructure.
For more information about Texas hurricanes (including tropical storms) going back to the 1500s, see Texas Hurricane History by David Roth of the National Weather Service.
For more interesting Hurricane records, see this post.
Posted by Bob Rehak on 8/27/2025 with research assistance from ChatGPT
2920 Days since Hurricane Harvey
MoCo Adopts New Drainage Criteria Manual 8 Years After Harvey
Montgomery County has finally updated its drainage criteria manual…eight years after Hurricane Harvey caused widespread flooding that exposed shortcomings in its previous manual which dated to the 1980s.
Unanimously Approved
MoCo Commissioners approved the new manual unanimously this morning. The draft of the new manual was first proposed in early 2024. That followed a minor update in 2019 from the county’s old 1988 drainage criteria manual in effect at the time of Harvey.
The new manual does not adopt all of the minimum drainage recommendations proposed by Harris County for areas draining into Harris, though it is a vast improvement over the previous iteration.
Minimum Drainage Requirements Proposed by Harris County
The minimum drainage requirements proposed by Harris County included five key measures:
1. Using Atlas 14 rainfall rates for sizing storm water conveyance and detention systems.
2. Requiring a minimum detention rate of 0.55 acre-feet per acre of detention for any new development on tracts one acre or larger. A single-family residential structure and accessory building proposed on an existing lot is exempt from providing detention.
3. Prohibiting the use of hydrograph timing as a substitute for detention on any project, unless it directly outfalls into Galveston Bay.
4. Requiring “no net fill” in the current mapped 500-year floodplain, except in areas identified as coastal zones only.
5. Requiring the minimum Finished Flood Elevation of new habitable structures be established at or waterproofed to the 500-year flood elevation as shown on the effective Flood Insurance Study.
Major Changes in New MoCo Drainage Criteria Manual
MoCo’s new drainage criteria manual includes some, but not all, of those recommendations.
It’s not perfect. But it’s a vast improvement. Assuming the county enforces them.
For ease of future reference, you can find Montgomery County’s new, updated Drainage Criteria Manual on the Reports page under the Regulations tab.
Suggestions by MoCo Resident
Montgomery County resident Chad Price addressed Commissioners Court before the vote. He applauded most of the updates in the manual. However, he also urged commissioners to adopt ALL of Harris County’s minimum requirements.
Price emphasized the uncertainty surrounding rainfall rates, the increasing frequency of storms that exceed predicted maximums, and flood maps that have yet to be updated to reflect Atlas-14.
He made two excellent points:
In that regard, Price urged commissioners to update building codes, require smarter drainage planning, preserve natural floodplains, and use science-based floodplain mapping. He said, “These steps will reduce long-term costs to taxpayers, protect property values, and most importantly, safeguard our communities.”
Next Up
Montgomery County’s Floodplain Manager currently shows floodplain regulations adopted in 2014. That’s before the Tax Day, Memorial Day, Harvey, Imelda and May Day 2024 floods. Given the thousands of homes in MoCo that flood repeatedly, there may be some opportunities for improvement in those floodplain regs.
Posted by Bob Rehak on 8/26/25
2919 Days since Hurricane Harvey
The thoughts expressed in this post represent opinions on matters of public concern and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas.