Alert archive / Colorado / Flash Flood Watches in 2021
Flash Flood Watch 9, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this flash flood watch at Aug 3, 2021, 3:41 AM MDT for 9 counties in Colorado. It took effect at Aug 3, 2021, 10:00 AM MDT. It was in force for 12 hr.
The area
The counties it named.
The facts
- Issued
- Aug 3, 2021, 3:41 AM MDT (09:41 UTC)
- In effect from
- Aug 3, 2021, 10:00 AM MDT
- Expired
- Aug 3, 2021, 10:00 PM MDT
- In force
- 12 hr
- Issued by
- NWS Denver/Boulder, CO
- Flood severity
- None
Counties Boulder County, CO, Clear Creek County, CO, Gilpin County, CO, Grand County, CO, Jackson County, CO, Jefferson County, CO, Larimer County, CO, Park County, CO, Summit County, CO
The radar
The Denver radar (KFTG), 102 km from the middle of the area, began a volume at 09:41 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.
The nearest sounding before it
Denver, CO (KDNR), launched 00:00Z, 9.7 hours before the alert went out and 213 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
- 3072 m above ground
- 0-6 km bulk shear
- 13 kt
- 0-1 km storm-relative helicity
- -25 m²/s²
- 0-3 km storm-relative helicity
- -57 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
195 WGUS65 KBOU 030941 FFABOU URGENT - IMMEDIATE BROADCAST REQUESTED Flood Watch National Weather Service Denver CO 341 AM MDT Tue Aug 3 2021 COZ030>034-037-031745- /O.NEW.KBOU.FF.A.0009.210803T1600Z-210804T0400Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Jackson County Below 9000 Feet-West Jackson and West Grand Counties Above 9000 Feet-Grand and Summit Counties Below 9000 Feet-South and East Jackson/Larimer/North and Northeast Grand/Northwest Boulder Counties Above 9000 Feet-South and Southeast Grand/West Central and Southwest Boulder/Gilpin/Clear Creek/Summit/North and West Park Counties Above 9000 Feet-Central and Southeast Park County- Including the cities of North Park, Hartsel, Rocky Mountain National Park, Mt Zirkel, Laramie and Medicine Bow Mountains, Breckenridge, Williams Fork Mountains, Indian Peaks, Eisenhower Tunnel, Kremmling, East Slopes Southern Gore Range, Mount Evans, Fairplay, Grand Lake, Cameron Pass, East Slopes Mosquito Range, Berthoud Pass, Winter Park, South Park, Granby, Hot Sulphur Springs, Kenosha Mountains, Gould, Willow Creek Pass, Spicer, Rand, Dillon, Fraser, Walden, Lake George, and Rabbit Ears Range 341 AM MDT Tue Aug 3 2021 ...FLASH FLOOD WATCH IN EFFECT FROM 10 AM MDT THIS MORNING THROUGH THIS EVENING... The National Weather Service in Denver has issued a * Flash Flood Watch for Portions of central and north central Colorado, including the following areas, in central Colorado, Central and Southeast Park County, Grand and Summit Counties Below 9000 Feet and South and Southeast Grand/West Central and Southwest Boulder/Gilpin/Clear Creek/Summit/North and West Park Counties Above 9000 Feet. In north central Colorado, Jackson County Below 9000 Feet, South and East Jackson/Larimer/North and Northeast Grand/Northwest Boulder Counties Above 9000 Feet and West Jackson and West Grand Counties Above 9000 Feet. * From 10 AM MDT this morning through this evening. * Slow moving thunderstorms capable of generating heavy rains are expected to occur off and on from late this morning into this evening. * Burn scars in Grand County are at an elevated risk of flash flooding and debris flows, though there is potential for flash flooding to occur across the area. PRECAUTIONARY/PREPAREDNESS ACTIONS... Turn around, don't drown when encountering flooded roads. Most flood deaths occur in vehicles. Move away from recently burned areas. Life-threatening flooding of creeks, roads and normally dry gulches is likely. The heavy rains will likely trigger rockslides, mudslides and debris flows in steep terrain. && $$ Schlatter
2 follow-up statements
864 WGUS65 KBOU 032018 FFABOU Flood Watch National Weather Service Denver CO 218 PM MDT Tue Aug 3 2021 COZ030>034-037-040400- /O.CON.KBOU.FF.A.0009.000000T0000Z-210804T0400Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Jackson County Below 9000 Feet-West Jackson and West Grand Counties Above 9000 Feet-Grand and Summit Counties Below 9000 Feet-South and East Jackson/Larimer/North and Northeast Grand/Northwest Boulder Counties Above 9000 Feet-South and Southeast Grand/West Central and Southwest Boulder/Gilpin/Clear Creek/Summit/North and West Park Counties Above 9000 Feet-Central and Southeast Park County- Including the cities of North Park, Hartsel, Rocky Mountain National Park, Mt Zirkel, Laramie and Medicine Bow Mountains, Breckenridge, Williams Fork Mountains, Indian Peaks, Eisenhower Tunnel, Kremmling, East Slopes Southern Gore Range, Mount Evans, Fairplay, Grand Lake, Cameron Pass, East Slopes Mosquito Range, Berthoud Pass, Winter Park, South Park, Granby, Hot Sulphur Springs, Kenosha Mountains, Gould, Willow Creek Pass, Spicer, Rand, Dillon, Fraser, Walden, Lake George, and Rabbit Ears Range 218 PM MDT Tue Aug 3 2021 ...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 10 PM MDT THIS EVENING... The Flash Flood Watch continues for * Portions of central and north central Colorado, including the following areas, in central Colorado, Central and Southeast Park County, Grand and Summit Counties Below 9000 Feet and South and Southeast Grand/West Central and Southwest Boulder/Gilpin/Clear Creek/Summit/North and West Park Counties Above 9000 Feet. In north central Colorado, Jackson County Below 9000 Feet, South and East Jackson/Larimer/North and Northeast Grand/Northwest Boulder Counties Above 9000 Feet and West Jackson and West Grand Counties Above 9000 Feet. * Until 10 PM MDT this evening. * Slow moving thunderstorms capable of generating heavy rains are expected to occur this afternoon and evening. * Burn scars in Grand County are at an elevated risk of flash flooding and debris flows, though there is potential for flash flooding to occur across the area. PRECAUTIONARY/PREPAREDNESS ACTIONS... Turn around, don't drown when encountering flooded roads. Most flood deaths occur in vehicles. Move away from recently burned areas. Life-threatening flooding of creeks, roads and normally dry gulches is likely. The heavy rains will likely trigger rockslides, mudslides and debris flows in steep terrain. && $$ Hiris
320 WGUS65 KBOU 040339 FFABOU Flood Watch National Weather Service Denver CO 939 PM MDT Tue Aug 3 2021 COZ030>034-037-040445- /O.EXP.KBOU.FF.A.0009.000000T0000Z-210804T0400Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Jackson County Below 9000 Feet-West Jackson and West Grand Counties Above 9000 Feet-Grand and Summit Counties Below 9000 Feet-South and East Jackson/Larimer/North and Northeast Grand/Northwest Boulder Counties Above 9000 Feet-South and Southeast Grand/West Central and Southwest Boulder/Gilpin/Clear Creek/Summit/North and West Park Counties Above 9000 Feet-Central and Southeast Park County- Including the cities of North Park, Hartsel, Rocky Mountain National Park, Mt Zirkel, Laramie and Medicine Bow Mountains, Breckenridge, Williams Fork Mountains, Indian Peaks, Eisenhower Tunnel, Kremmling, East Slopes Southern Gore Range, Mount Evans, Fairplay, Grand Lake, Cameron Pass, East Slopes Mosquito Range, Berthoud Pass, Winter Park, South Park, Granby, Hot Sulphur Springs, Kenosha Mountains, Gould, Willow Creek Pass, Spicer, Rand, Dillon, Fraser, Walden, Lake George, and Rabbit Ears Range 939 PM MDT Tue Aug 3 2021 ...FLASH FLOOD WATCH WILL EXPIRE AT 10 PM MDT THIS EVENING... The Flash Flood Watch for Portions of central and north central Colorado, including the following areas, in central Colorado, Central and Southeast Park County, Grand and Summit Counties Below 9000 Feet and South and Southeast Grand/West Central and Southwest Boulder/Gilpin/Clear Creek/Summit/North and West Park Counties Above 9000 Feet. In north central Colorado, Jackson County Below 9000 Feet, South and East Jackson/Larimer/North and Northeast Grand/Northwest Boulder Counties Above 9000 Feet and West Jackson and West Grand Counties Above 9000 Feet. will expire at 10 PM MDT this evening. Flooding is no longer expected to pose a threat. Please continue to heed remaining road closures. $$ RJK
The office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 2, 6:26 PM MDT | Flash Flood Warning | BOU | Larimer | 116 min |
| Aug 3, 8:10 AM MDT | Areal Flood Advisory | BOU | Grand | 3 hr |
| Aug 3, 2:22 PM MDT | Areal Flood Advisory | BOU | Douglas, Jefferson | 113 min |
| Aug 3, 2:58 PM MDT | Flash Flood Warning | BOU | Elbert | 2 hr |
| Aug 3, 3:48 PM MDT | Areal Flood Advisory | BOU | Adams, Arapahoe, Elbert | 87 min |
| Aug 3, 4:05 PM MDT | Flash Flood Warning | BOU | Adams, Arapahoe | 115 min |
Nearby
Flash Flood Watches in Colorado, 2021Every flash flood watch 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.