Name: Flash Flood and Lightning Strikes in Texas, August 16, 2021
Start: 2021-08-16T14:59
End: 2021-08-16T16:40
Location: Texas

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

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The toll

Deaths: 0
Injuries: 0
Property damage: $51,000
Crop damage: None recorded
Events: 3

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS HGX wrote it up.

Widespread street flooding occurred across the City of Houston as the collision of two boundaries resulted in the development of near-stationary strong thunderstorms. Additionally, frequent lightning strikes resulted in some property damage.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Houston/Galveston, TX wrote its last area forecast discussion before the first event at Aug 16, 1:42 PM CST, 1 hour 17 minutes earlier.

Area forecast discussion, Aug 16, 1:42 PM CST, 1 hour 17 minutes before

Area Forecast Discussion
National Weather Service Houston/Galveston TX
242 PM CDT Mon Aug 16 2021

.SHORT TERM [Through Tuesday Night]...
Ongoing showers and tstms across the area should taper off this
evening with the loss of heating. Considering that the overall
pattern remains about the same, a continued forecast of persistence
still looks to be the way to go. Mid/upper trof stretching from
the Great Lakes into Tx, PW's 1.8-2.2", seabreeze and daytime
heating will contribute to diurnally driven shra/tstms again
Tues. Overnight lows 75-81 and daytime highs in the 90s.  47

&&

.LONG TERM [Wednesday Through Monday]...
An elongated upper level ridge will build across the Gulf Coast
states through the extended period, bringing with it seasonably hot
and humid conditions. We will also see a fairly typical increase in
showers and thunderstorms, especially nearer the coast, each afternoon
with diminishing PoPs after dark. While TS Grace will bear watching,
the building e-w upper ridge axis should shunt the system well
south on a more wwd track out of the Caribbean and across the far
southern Gulf into Mexico. The latest NHC tracks continue to trend
this way today, in which case the system would bring few if any
tangible impacts to SETX outside of increasing swells and surf
along the beaches. As the ridge builds this weekend, it will also
increase temperatures and wouldn't be surprised if we see heat
indicies near advisory criteria Saturday into Monday.

Evans

&&

.MARINE...
2-4ft/9-11s swell associated with Fred will move wwd across the
waters tonight into Wed morning. Otherwise, pressure gradient will
begin tightening and onshore flow will strengthen as we head into
the mid-late week time period. Onshore winds will increase and
we'll see a corresponding increase in seas - possibly to caution
criteria at times.

TD Grace is currently forecast to strengthen into a TS and move
w/wnw across the Yucatan Wed night and toward the eastern coast of
Mexico Fri night and Saturday. Local marine fcst details obviously
depend on its eventual track/intensity, but assuming current fcst
is in the ballpark, we should see an increasing swell arriving
Thurs night...peaking Fri night or early Sat. WWIII & ECMWF wave
models in fairly good agreement w/ 6-8ft seas at this point. ICON
is lower, but again...all dependent on the specifics.  47

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  75  94  76  92  77 /  20  40  30  50  10
Houston (IAH)          76  95  78  93  79 /  20  50  30  60  20
Galveston (GLS)        81  91  81  91  83 /  40  40  30  50  30

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.

&&

The radar

The Houston radar (KHGX), 56 km away, was scanning. The volume nearest the first event began at 20:57 UTC.

Open the radar archive at this moment

Event by event

2 lightning, 1 flash flood. Local standard time, as filed.

Lightning, Harris

When: August 16, 2:59 PM CST
Where: Harris County, Spring Branch
Property damage: $50,000
Reported by: Fire Department/Rescue
Coordinates: 29.800, -95.520

A home caught fire after bring struck by lightning.

Lightning, Harris

When: August 16, 3:00 PM CST
Where: Harris County, 0.96 mi WSW of Spring Vly
Property damage: $1,000
Reported by: Broadcast Media
Coordinates: 29.765, -95.515

Lightning struck and split a large pine tree.

Flash Flood, Harris

When: August 16, 3:55 PM CST to 4:40 PM CST
Where: Harris County, 1.38 mi N of Bunker Hill to 1.38 mi ESE of White Oak Acres
Cause: Heavy Rain
Reported by: Broadcast Media
Coordinates: 29.750, -95.530

Numerous roads were impassable due to floodwaters across the Houston area, especially in and around the West University Place and Galleria areas. Many vehicles were stalled due to the rapid rise of water levels.

What these are

Lightning: A lightning strike that killed, injured or caused damage.
Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Texas in 2021 Every state in 2021 This day in weather history Warnings in Texas, August 2021

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 966347, 966833, 966346.