Flash Flood Watch: Extreme Rainfall Possible Thru Wednesday Morning

6/14/2026 – The entire Houston region is under a flash flood watch until Wednesday morning, 6/17/26, according to Jeff Lindner, Harris County’s Meteorologist.

Weak tropical circulation from northeastern Mexico is lifting northward into south Texas on Monday and Tuesday while a weak front from the north stalls over our area.

Deep tropical moisture colliding with the front will create intense downpours at times. “Widespread rainfall amounts of 2-5 inches will be possible with isolated totals of 6-8 inches and this may need to be increased,” says Lindner. “Some models suggest upwards of 9-11 inches of rainfall in isolated locations by Tuesday morning.”

Lindner warns people not to try to figure out the exact locations for the heaviest rain, but instead to focus on the overall potential.

The models are increasingly signaling heavy rains and flash flooding. “This sort of setup in a tropical air mass can result in rapid onset flash flooding with significant hourly rainfall rates and totals,” he says. So, stay tuned to forecasts before you venture out.  

What is Flash Flooding?

Flooding is often categorized by how quickly it develops, what causes it, and how long it lasts. The key distinction is that flash flooding happens very rapidly, often with little or no warning.

It begins within minutes to a few hours after intense rainfall, a dam failure, or another sudden water release.

Key characteristics include:

• Develops in less than 6 hours, often in 30 minutes to 3 hours.
• Usually caused by very intense rainfall over a small area.
• Water rises rapidly and can move at high velocities.
• Often occurs in:
  • Urban areas with lots of pavement
  • Small watersheds
  • Gullies, and normally dry channels

Don’t drive into water where you can’t see the road. Turn around don’t drown.

Why It’s Dangerous

Flash flooding can happen with little warning time. Fast-moving water can sweep away vehicles and people. It accounts for a large share of flood-related deaths.

We’ve had several recent examples in Houston. During parts of the 2015 Memorial Day Flood and 2016 Tax Day Flood, some bayous and streets flooded within hours of intense rainfall, producing flash-flood conditions.

Other Types of Flooding

Hydrologists distinguish flash flooding from several other types of flooding. Houstonians should know the differences, so they can better understand weather warnings.

• River (Fluvial) Flooding
  • Caused when rivers, creeks, or bayous exceed their banks. It:
    • Develops over hours, days, or even weeks.
    • Usually results from rainfall over a large watershed.
    • Often more predictable than flash flooding.
    • Can last days or weeks.
  • Example: Hurricane Harvey when rivers carried enormous volumes of water downstream
• Urban Flooding
  • Occurs when rainfall overwhelms storm drains, roadside ditches, and local drainage systems.
  • Common in highly developed areas.
    • Can occur even when nearby rivers stay within their banks.
    • Often accompanies flash flooding.
    • Water collects in streets, underpasses, and low spots.
  • Many Houston-area street floods are urban flooding events rather than river floods.
• Coastal Flooding
  • Caused by seawater moving onto normally dry land from:
    • Storm surge from hurricanes
    • High tides
    • Sea-level rise
  • Most common near bays and coastlines.
  • Saltwater flooding can damage infrastructure and ecosystems.
  • Example: Coastal and bay areas during Hurricane Ike.
• Pluvial Flooding
  • Occurs directly from rainfall accumulating on the ground before it reaches a stream or drainage system
    • Can occur far from rivers.
    • Happens when rainfall exceeds infiltration and drainage capacity.
    • Frequently overlaps with urban flooding.
  • Example: A subdivision may flood because rainwater ponds in streets and yards even though no nearby creek overflows.
• Backwater Flooding
  • Caused when high water downstream slows drainage upstream.
    • Common in flat areas with low gradients.
    • Water “backs up” into tributaries, ditches, and neighborhoods.
    • Often worsens flooding duration
  • Examples: Lower reaches of Spring Creek, Cypress Creek, and portions of the San Jacinto River can experience backwater effects because of the region’s very low slope and interactions with Lake Houston.

Lake and Other Reports

As of 4PM on Sunday 6/14/26, Lake Conroe is not pre-releasing any water.

For updates see the homepage at SJRA.net.

Lake Houston is pre-releasing only a small amount.

For Lake Houston updates, visit https://www.coastalwaterauthority.org.

For tropical updates, visit the National Hurricane Center at https://www.nhc.noaa.gov.

Be on high alert until the flash flood watch expires. Check weather forecasts frequently.

To see how rainfall accumulations affect rivers, streams and channels around you, check the Harris County Flood Warning System at https://www.harriscountyfws.org. When you visit the home page, you can see rainfall accumulations around the region. Click on “Channels” in the upper left to see the status of streams, rivers, and bayous near you.

Posted by Bob Rehak on 6/14/26

3211 Days since Hurricane Harvey