A slow moving upper low over the Southwestern U.S. combined with near record level moisture aided in producing extremely heavy rainfall and devastating flooding over portions of Harris, Waller and Fort Bend Counties. Northwest to southeast orientated bands of precipitation commenced during the early evening hours of April 17th across extreme southwestern and western Harris County as well as north and west into Grimes, Waller, Fort Bend, Austin and Colorado Counties. Between 8:00 p.m. and 9:00 p.m. thunderstorms began to greatly intensify and slow their northward movement over Waller County and, by late evening, had stalled and began shifting eastward into western Harris County. Excessive rainfall spread across northwestern Harris County during the late evening hours of April 17th and into the early morning hours of April 18th. Slow thunderstorm movement and rain rates over 4 inches per hour resulted in a large portion of northwest Harris and Waller Counties receiving between 10 and 20 inches of rainfall over mainly a 12 hour period. A few CoCoRaHS gauges in Waller County measured over 20 inches.
The flooding resulted in 8 direct fatalities over the region, all drownings in vehicles. Six of these were in Harris County with 1 in Waller County and another in Austin County. An estimated 40000 cars and trucks were flooded. Several bayous and creeks were flooded. The Addicks Barker Reservoir was severely impacted. At least 10,000 homes were flooded. Damage was estimated from Damage Survey Reports to be near $60 million.

Tornado in HARRIS, TEXAS
From 18-APR-16 04:14:00 to 18-APR-16 04:16:00 (CST-6)
Location: HUFFMAN
Tornado F-scale: EF0
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Tornado moved through residential area near Huffman with damage mainly along Waterway Street. A few trees were uprooted, many branches down.

Tornado in HARRIS, TEXAS
From 17-APR-16 11:10:00 to 17-APR-16 11:12:00 (CST-6)
Location: SPRING SKYLINE ARPT
Tornado F-scale: EF0
Property damage: 30.00K
Crop damage: 0.00K
Reported by: County Official

Weak tornado damaged Klein Collins High School. Well defined path across school and into adjacent subdivision.

Flash Flood in HARRIS, TEXAS
From 17-APR-16 23:00:00 to 18-APR-16 11:00:00 (CST-6)
Location: HOCKLEY
Flood cause: Heavy Rain
Property damage: 35.00M
Crop damage: 0.00K
Reported by: County Official

Heavy rain caused extensive flooding especially over western half of the county where 10 to 15 inches of rain fell in less than a 12 hour period. An estimated 40,000 vehicles and 10,000 homes were flooded. Seven people in Harris County drowned in their vehicles when they drove into flooded roadways. There were numerous high water rescues.

Flash Flood in GRIMES, TEXAS
From 18-APR-16 02:00:00 to 18-APR-16 10:00:00 (CST-6)
Location: TODD MISSION
Flood cause: Heavy Rain
Property damage: 800.00K
Crop damage: 0.00K
Reported by: Department of Highways

There were water rescues in the Todd Mission area. Major flooding occurred along County Road 311 northwest of Todd Mission with water halfway up the street signage.

Flash Flood in FORT BEND, TEXAS
From 18-APR-16 06:00:00 to 18-APR-16 12:00:00 (CST-6)
Location: SUGARLAND
Flood cause: Heavy Rain
Property damage: 992.00K
Crop damage: 0.00K
Reported by: Law Enforcement

The Brazos River turnaround at Highway 59, along with the Highway 90 underpass between Richmond and Rosenberg and Highway 90A at Highway 99, were all impassable due to flooding.

Thunderstorm Wind in HARRIS, TEXAS
From 17-APR-16 23:05:00 to 17-APR-16 23:05:00 (CST-6)
Location: KORVILLE
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A large pine tree was snapped off along Highway 249 between Northpointe Blvd and Canyon Gates Point Driver.

Flash Flood in MONTGOMERY, TEXAS
From 18-APR-16 03:30:00 to 18-APR-16 09:30:00 (CST-6)
Location: MOSTYN
Flood cause: Heavy Rain
Property damage: 3.00M
Crop damage: 0.00K
Reported by: Law Enforcement

FM 1774 was flooded just west of Magnolia near the Montgomery and Waller County line.

Flash Flood in WALLER, TEXAS
From 18-APR-16 02:00:00 to 18-APR-16 08:00:00 (CST-6)
Location: HEMPSTEAD
Flood cause: Heavy Rain
Property damage: 6.70M
Crop damage: 10.00K
Reported by: Local Official

Flooding closed Highway 290 at the Harris and Waller County line. FM 362, FM 359 and FM 527 were all flooded.

Flash Flood in GALVESTON, TEXAS
From 18-APR-16 07:00:00 to 18-APR-16 15:00:00 (CST-6)
Location: LEAGUE CITY S S ARPT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Numerous flooded roadways in League City. Flood waters were inundating numerous roads within the city of Galveston.

Flash Flood in COLORADO, TEXAS
From 18-APR-16 03:00:00 to 18-APR-16 09:00:00 (CST-6)
Location: WEIMAR
Flood cause: Heavy Rain
Property damage: 2.50M
Crop damage: 0.00K
Reported by: Law Enforcement

Numerous roads and bridges were closed and water rescues were performed due to flooding across northern portions of the county. The FM 109 bridge over Cummings Creek, just north of Brunes Mill Road north of Columbus, was completely washed out.

Flash Flood in AUSTIN, TEXAS
From 18-APR-16 01:00:00 to 18-APR-16 09:00:00 (CST-6)
Location: BUCKHORN
Flood cause: Heavy Rain
Property damage: 2.30M
Crop damage: 0.00K
Reported by: Law Enforcement

The following roads either inundated with water and/or closed due to being flooded; FM 2429 south of Bellville, FM 529 and FM 331 east of Bellville. A report at 0309 CST stated that that there were numerous road closures due to flooding across a large part of the county, especially over the central and north part of the county. A female resident drowned when driving into high water on Plumb Creek Road. Damage amounts estimated.

Tornado in HARRIS, TEXAS
From 18-APR-16 04:12:00 to 18-APR-16 04:14:00 (CST-6)
Location: LAKE HOUSTON
Tornado F-scale: EF0
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Public

Minor damage occurred in the Summerwood neighborhood near Lake Houston. Trees and fences blown down. One home sustained roof damage.