Alert archive / Utah / Flash Flood Warnings in 2021
Flash Flood Warning 120, NWS Salt Lake City, UT
NWS Salt Lake City, UT issued this flash flood warning at Aug 18, 2021, 11:11 PM MDT for Kane County, Washington County, Utah. It was in force for 5 hr. 2 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Aug 18, 2021, 11:11 PM MDT (05:11 UTC)
- Expired
- Aug 19, 2021, 4:15 AM MDT
- In force
- 5 hr
- Issued by
- NWS Salt Lake City, UT
- Area
- Storm-based polygon
- Damage threat
- Considerable
- Flood severity
- None
Counties Kane County, UT, Washington County, UT
The radar
The Cedar City radar (KICX), 40 km from the middle of the area, began a volume at 05:13 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 19, 4:00 AM MDT | FLASH FLOOD | 2 Ssw Zion Np, UT | ZION NP DISPATCH REPORTED A ROCKSLIDE DUE TO EXCESSIVE RAINFALL ALONG THE SCENIC DRIVE NORTH OF THE VISITOR CENTER. A PORTION OF THE ROAD WAS DAMAGED DUE TO THE SLIDE AND IS CLOSED AS A RESULT. LOCATION APPROXIMATE. TIME ESTIMATED BY RADAR. |
| Aug 19, 4:15 AM MDT | FLASH FLOOD | 2 Nne Springdale, UT | THE RIVER GAGE ON THE NORTH FORK OF THE VIRGIN RIVER NEAR SPRINGDALE HAD A SHARP RISE AND PEAKED AT 1690 CFS. THIS CORRESPONDS TO A RISE OF OVER 3 FEET. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Las Vegas, NV (KVEF), launched 00:00Z, 5.2 hours before the alert went out and 247 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 3543 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 11 m²/s²
- 0-3 km storm-relative helicity
- 14 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
666
WGUS55 KSLC 190511
FFWSLC
UTC025-053-190915-
/O.NEW.KSLC.FF.W.0120.210819T0511Z-210819T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
1111 PM MDT Wed Aug 18 2021
The National Weather Service in Salt Lake City has issued a
* Flash Flood Warning for...
West Central Kane County in southern Utah...
East Central Washington County in southwestern Utah...
* Until 315 AM MDT.
* At 1111 PM MDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 0.25 and 0.5 inches of
rain have fallen. Additional rainfall amounts of 0.5 to 1 inch are
possible in the warned area. Flash flooding is ongoing or expected
to begin shortly.
HAZARD...Life threatening flash flooding. Thunderstorms
producing flash flooding.
SOURCE...Radar.
IMPACT...Life threatening flash flooding of creeks and streams
across Zion National Park.
* Some locations that will experience flash flooding include...
Zion National Park, Springdale and Rockville.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 3714 11297 3721 11315 3731 11322 3735 11308
3739 11305 3740 11281 3715 11278 3710 11283
FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
$$
MPS3 follow-up statements
367
WGUS75 KSLC 190707
FFSSLC
Flash Flood Statement
National Weather Service Salt Lake City UT
107 AM MDT Thu Aug 19 2021
UTC025-053-190915-
/O.CON.KSLC.FF.W.0120.000000T0000Z-210819T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kane UT-Washington UT-
107 AM MDT Thu Aug 19 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 315 AM MDT EARLY THIS
MORNING FOR WEST CENTRAL KANE AND EAST CENTRAL WASHINGTON COUNTIES...
At 107 AM MDT, Doppler radar indicated thunderstorms producing heavy
rain in Zion National Park. Between 0.5 and 1 inch of rain has
fallen in the park, while 1 to 2.5 inches has fallen outside of the
park along the North Fork and East Fork Virgin River drainages.
Flash flooding is ongoing or expected to begin shortly.
HAZARD...Life threatening flash flooding. Thunderstorms producing
flash flooding.
SOURCE...Radar.
IMPACT...Life threatening flash flooding of creeks and streams
across Zion National Park.
Some locations that will experience flash flooding include...
Zion National Park, Springdale and Rockville.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 3714 11297 3721 11315 3731 11322 3735 11308
3739 11305 3740 11281 3715 11278 3710 11283
FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
$$
LC917
WGUS55 KSLC 190912
FFWSLC
UTC025-053-191015-
/O.EXT.KSLC.FF.W.0120.000000T0000Z-210819T1015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Salt Lake City UT
312 AM MDT Thu Aug 19 2021
The National Weather Service in Salt Lake City has extended the
* Flash Flood Warning for...
West Central Kane County in southern Utah...
East Central Washington County in southwestern Utah...
* Until 415 AM MDT.
* At 312 AM MDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 0.5 and 1 inch of rain
has fallen in the park, while 1 to 2.5 inches have fallen outside
of the park along the North Fork and East Fork Virgin River
drainages. A river gage on the North Fork within the park
indicates the river beginning to rise, while a gage on the East
Fork outside of the park shows a significant rise. The flood waves
from both streams should be making their way through Zion over the
next hour. Flash flooding is ongoing or expected to begin shortly.
HAZARD...Life threatening flash flooding. Thunderstorms
producing flash flooding.
SOURCE...Radar.
IMPACT...Life threatening flash flooding of creeks and streams
across Zion National Park.
* Some locations that will experience flash flooding include...
Zion National Park, Springdale and Rockville.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 3714 11297 3721 11315 3731 11322 3735 11308
3739 11305 3740 11281 3715 11278 3710 11283
FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
$$
LC233
WGUS75 KSLC 191014
FFSSLC
Flash Flood Statement
National Weather Service Salt Lake City UT
414 AM MDT Thu Aug 19 2021
UTC025-053-191024-
/O.EXP.KSLC.FF.W.0120.000000T0000Z-210819T1015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kane UT-Washington UT-
414 AM MDT Thu Aug 19 2021
...FLASH FLOOD WARNING WILL EXPIRE AT 415 AM MDT EARLY THIS MORNING
FOR WEST CENTRAL KANE AND EAST CENTRAL WASHINGTON COUNTIES...
The heavy rain has ended over Zion National Park. Additional
flooding is no longer expected. However, runoff from earlier heavy
rain and flash flooding will continue to move through the North Fork
and East Fork Virgin Rivers before gradually decreasing into the
early morning hours. Please continue to heed any remaining road
closures.
A Flash Flood Watch remains in effect until 600 AM MDT for portions
of central Utah, northern Utah and southern Utah.
A Flash Flood Watch remains in effect until 600 AM MDT for a portion
of southwest Utah.
LAT...LON 3714 11297 3721 11315 3731 11322 3735 11308
3739 11305 3740 11281 3715 11278 3710 11283
$$
LCThe office that day
Everything else NWS Salt Lake City, UT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 18, 7:43 PM MDT | Flash Flood Warning | SLC | Kane | 4 hr |
| Aug 18, 8:01 PM MDT | Flash Flood Warning | SLC | Garfield | 3 hr |
| Aug 18, 8:46 PM MDT | Special Weather Statement | SLC | Iron | 44 min |
| Aug 18, 9:39 PM MDT | Flash Flood Warning | SLC | Iron, Washington | 3 hr |
| Aug 18, 9:48 PM MDT | Areal Flood Advisory | SLC | Iron | 5 min |
| Aug 18, 9:53 PM MDT | Flash Flood Warning | SLC | Iron | 3 hr |
| Aug 18, 10:07 PM MDT | Flash Flood Warning | SLC | Iron | 3 hr |
| Aug 19, 1:43 AM MDT | Flash Flood Warning | SLC | Garfield, Wayne | 3 hr |
| Aug 19, 2:03 AM MDT | Flash Flood Warning | SLC | Garfield, Kane, San Juan | 6 hr |
| Aug 19, 2:31 AM MDT | Flash Flood Warning | SLC | Kane | 3 hr |
| Aug 19, 3:50 AM MDT | Special Weather Statement | SLC | 25 min | |
| Aug 19, 9:39 AM MDT | Special Weather Statement | SLC | Kane | 36 min |
| Aug 19, 10:16 AM MDT | River Flood Warning | SLC | Duchesne | 4 hr |
| Aug 19, 10:54 AM MDT | Special Weather Statement | SLC | Juab | 51 min |
| Aug 19, 11:15 AM MDT | Areal Flood Advisory | SLC | Millard | 2 hr |
| Aug 19, 11:42 AM MDT | Special Weather Statement | SLC | Sanpete | 48 min |
| Aug 19, 12:29 PM MDT | Special Weather Statement | SLC | Sanpete | 46 min |
| Aug 19, 12:49 PM MDT | Flash Flood Warning | SLC | Garfield, Wayne | 3 hr |
| Aug 19, 1:04 PM MDT | Special Weather Statement | SLC | Utah | 56 min |
| Aug 19, 1:25 PM MDT | Special Weather Statement | SLC | Carbon | 50 min |
| Aug 19, 2:12 PM MDT | Special Weather Statement | SLC | Carbon, Duchesne | 63 min |
| Aug 19, 2:59 PM MDT | Special Weather Statement | SLC | Duchesne | 61 min |
Nearby
Flash Flood Warnings in Utah, 2021Every flash flood warning in 2021
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.