Alert archive / Utah / Flash Flood Warnings in 2021
Flash Flood Warning 71, NWS Grand Junction, CO
NWS Grand Junction, CO issued this flash flood warning at Aug 1, 2021, 8:56 PM MDT for Grand County, San Juan County, Utah. It was in force for 109 min. 1 report 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 1, 2021, 8:56 PM MDT (02:56 UTC)
- Expired
- Aug 1, 2021, 10:45 PM MDT
- In force
- 109 min
- Issued by
- NWS Grand Junction, CO
- Area
- Storm-based polygon
- Damage threat
- Considerable
- Flood severity
- None
Counties Grand County, UT, San Juan County, UT
The radar
The Grand Junction radar (KGJX), 115 km from the middle of the area, began a volume at 02:55 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 1, 9:30 PM MDT | FLASH FLOOD | 4 Se Grand Co Arpt, UT | LARGE MUD AND DEBRIS FLOW FROM THE PACK CREEK WILDFIRE BURN SCAR BREACHED THE PACK CREEK BRIDGE. THIS FLOW IS BIGGER THAN THE ONE LAST WEEK. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Grand Junction, CO (KGJT), launched 00:00Z, 2.9 hours before the alert went out and 101 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
- 162 J/kg
- Mixed-layer CIN
- -30 J/kg
- Mixed-layer LCL
- 2258 m above ground
- 0-6 km bulk shear
- 22 kt
- 0-1 km storm-relative helicity
- 49 m²/s²
- 0-3 km storm-relative helicity
- 56 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
127
WGUS55 KGJT 020256
FFWGJT
UTC019-037-020445-
/O.NEW.KGJT.FF.W.0071.210802T0256Z-210802T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Grand Junction CO
856 PM MDT Sun Aug 1 2021
The National Weather Service in Grand Junction has issued a
* Flash Flood Warning for...
The Pack Creek Fire Burn Area in...
Southeastern Grand County in east central Utah...
Northeastern San Juan County in southeastern Utah...
* Until 1045 PM MDT.
* At 856 PM MDT, Doppler radar indicated thunderstorms producing
heavy rain over the Pack Creek Fire Burn Area. Between 0.2 and 0.5
inches of rain has fallen. The expected rainfall rate is 1 to 1.5
inches in 1 hour. Additional rainfall amounts of 0.5 to 1.5 inches
are possible in the warned area. Flash flooding is ongoing or
expected to begin shortly.
Excessive rainfall over the burn scar will result in debris flow
moving through the Pack Creek Burn Area. The debris flow can consist
of rock, mud, vegetation and other loose materials.
HAZARD...Life threatening flash flooding. Thunderstorms
producing flash flooding in and around the Pack Creek
Fire Burn Area.
SOURCE...Radar.
IMPACT...Life threatening flash flooding of areas in and around
the Pack Creek Fire Burn Area.
* Some locations that will experience flash flooding include...
Spanish Valley.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
This is a life threatening situation. Heavy rainfall will cause
extensive and severe flash flooding of creeks...streams...and
ditches in the Pack Creek Fire Burn Area. Severe debris flows can
also be anticipated across roads. Roads and driveways may be washed
away in places. If you encounter flood waters...climb to safety.
Move away from recently burned areas. Life-threatening flooding of
creeks, roads and normally dry arroyos is likely. The heavy rains
will likely trigger rockslides, mudslides and debris flows in steep
terrain, especially in and around these areas.
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Be especially cautious at night when it is harder to recognize the
dangers of flooding.
&&
LAT...LON 3850 10927 3851 10926 3850 10922 3844 10923
3844 10926 3845 10928 3842 10932 3843 10939
3845 10939 3847 10934 3848 10930
FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...1-1.5 INCHES IN 1 HOUR
$$
BWM2 follow-up statements
245
WGUS75 KGJT 020352
FFSGJT
Flash Flood Statement
National Weather Service Grand Junction CO
952 PM MDT Sun Aug 1 2021
UTC019-037-020445-
/O.CON.KGJT.FF.W.0071.000000T0000Z-210802T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Grand UT-San Juan UT-
952 PM MDT Sun Aug 1 2021
...FLASH FLOOD WARNING FOR THE PACK CREEK FIRE BURN AREA REMAINS IN
EFFECT UNTIL 1045 PM MDT THIS EVENING FOR SOUTHEASTERN GRAND AND
NORTHEASTERN SAN JUAN COUNTIES...
At 952 PM MDT, Emergency management reported a large flash flood,
mud and debris flow was moving down the Pack Creek and breached the
Pack Creek bridge.
Doppler radar indicated thunderstorms producing heavy rain over the
Pack Creek Fire Burn Area. Between 1 and 1.5 inches of rain has
fallen since 830 pm. The expected rainfall rate is 0.2 to 0.5 inches
in 1 hour. Additional rainfall amounts of 0.2 to 0.6 inches are
possible in the warned area. Flash flooding is ongoing or expected
to begin shortly.
Excessive rainfall over the burn scar will result in debris flow
moving through the Pack Creek Burn Area. The debris flow can consist
of rock, mud, vegetation and other loose materials.
HAZARD...Life threatening flash flooding. Thunderstorms producing
flash flooding in and around the Pack Creek Fire Burn
Area.
SOURCE...Radar.
IMPACT...Life threatening flash flooding of areas in and around
the Pack Creek Fire Burn Area.
Some locations that will experience flash flooding include...
Spanish Valley.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
This is a life threatening situation. Heavy rainfall will cause
extensive and severe flash flooding of creeks...streams...and
ditches in the Pack Creek Fire Burn Area. Severe debris flows can
also be anticipated across roads. Roads and driveways may be washed
away in places. If you encounter flood waters...climb to safety.
Move away from recently burned areas. Life-threatening flooding of
creeks, roads and normally dry arroyos is likely. The heavy rains
will likely trigger rockslides, mudslides and debris flows in steep
terrain, especially in and around these areas.
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Be especially cautious at night when it is harder to recognize the
dangers of flooding.
&&
LAT...LON 3850 10927 3851 10926 3850 10922 3844 10923
3844 10926 3845 10928 3842 10932 3843 10939
3845 10939 3847 10934 3848 10930
FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...0.2-0.5 INCHES IN 1 HOUR
$$
BWM090
WGUS75 KGJT 020443
FFSGJT
Flash Flood Statement
National Weather Service Grand Junction CO
1043 PM MDT Sun Aug 1 2021
UTC019-037-020453-
/O.EXP.KGJT.FF.W.0071.000000T0000Z-210802T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Grand UT-San Juan UT-
1043 PM MDT Sun Aug 1 2021
...FLASH FLOOD WARNING FOR THE PACK CREEK FIRE BURN AREA WILL EXPIRE
AT 1045 PM MDT THIS EVENING FOR SOUTHEASTERN GRAND AND NORTHEASTERN
SAN JUAN COUNTIES...
The heavy rain has ended. Flooding is no longer expected to pose a
threat. However, please continue to stay away from swiftly flowing
water and mud flows that may still be moving down creek beds, and
heed any remaining road closures.
LAT...LON 3850 10927 3851 10926 3850 10922 3844 10923
3844 10926 3845 10928 3842 10932 3843 10939
3845 10939 3847 10934 3848 10930
$$
BWMThe office that day
Everything else NWS Grand Junction, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 1, 6:35 PM MDT | Areal Flood Advisory | GJT | Uintah | 115 min |
| Aug 1, 6:41 PM MDT | Special Weather Statement | GJT | Uintah | 34 min |
| Aug 1, 7:03 PM MDT | Areal Flood Advisory | GJT | Grand | 3 hr |
| Aug 1, 11:10 PM MDT | Flash Flood Warning | GJT | Grand, San Juan | 3 hr |
| Aug 2, 1:17 PM MDT | Areal Flood Advisory | GJT | Grand, San Juan | 118 min |
| Aug 2, 1:29 PM MDT | Areal Flood Advisory | GJT | San Juan | 2 hr |
| Aug 2, 4:37 PM MDT | Areal Flood Advisory | GJT | Uintah | 2 hr |
| Aug 2, 5:12 PM MDT | Special Weather Statement | GJT | San Juan | 48 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.