Alert archive / Colorado / Flash Flood Warnings in 2017

Flash Flood Warning 7, NWS Denver/Boulder, CO

August 10, 2017Larimer County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Aug 10, 2017, 2:31 PM MDT for Larimer County, Colorado. It was in force for 119 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 10, 2017, 2:31 PM MDT (20:31 UTC)
Expired: Aug 10, 2017, 4:30 PM MDT
In force: 119 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Flood severity: None

County Larimer County, CO

The radar

The Cheyenne radar (KCYS), 74 km from the middle of the area, began a volume at 20:34 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 (KDEN), launched 12:00Z, 8.5 hours before the alert went out and 203 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 2 J/kg
Mixed-layer CIN: -251 J/kg
Mixed-layer LCL: 866 m above ground
0-6 km bulk shear: 46 kt
0-1 km storm-relative helicity: 26 m²/s²
0-3 km storm-relative helicity: 76 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

783 
WGUS55 KBOU 102031
FFWBOU
COC069-102230-
/O.NEW.KBOU.FF.W.0007.170810T2031Z-170810T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
231 PM MDT THU AUG 10 2017

The National Weather Service in Denver Colorado has issued a

* Flash Flood Warning for...
  East central Larimer County in north central Colorado...

* Until 430 PM MDT

* At 230 PM MDT, Doppler radar indicated thunderstorms producing
  heavy rain 4 miles west of Mishawaka. The rain is moving southeast
  at 25 mph. Flash flooding is expected to begin shortly.

* Some locations that will experience flooding include...
  Poudre Park, Buckhorn Mountain and Mishawaka. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Heavy rainfall will cause flash flooding of creeks, streams, roads
and culverts in the High Park burn area. Some areas affected include
Rist Canyon, Buckhorn Creek, Redstone Canyon, Stove Prairie, and
gulches draining into the Poudre Canyon along highway 14. Rock slides
or debris flows can also be expected across roads in the burn area.

Flooding is occurring or is imminent. It is important to know where 
you are relative to streams, rivers, or creeks which can become 
killers in heavy rains. Campers and hikers should avoid streams or 
creeks.

&&

LAT...LON 4073 10554 4078 10543 4069 10522 4053 10517
      4045 10542

$$

GIMMESTAD

2 follow-up statements

347 
WGUS75 KBOU 102137
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
337 PM MDT THU AUG 10 2017

COC069-102230-
/O.CON.KBOU.FF.W.0007.000000T0000Z-170810T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Larimer CO-
337 PM MDT THU AUG 10 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 430 PM MDT FOR
EAST CENTRAL LARIMER COUNTY...

At 335 PM MDT, Heavy rain had moved out of the High Park burn area. 
Flash flooding is likely occurring in the northern and eastern parts 
of the burn area, where one half to one inch of rain fell in less 
than 30 minutes.

Some locations that will experience flooding include...
Poudre Park, Buckhorn Mountain and Mishawaka. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Heavy rainfall will cause flash flooding of creeks, streams, roads
and culverts in the High Park burn area. Some areas affected include
Rist Canyon, Buckhorn Creek, Redstone Canyon, Stove Prairie, and
gulches draining into the Poudre Canyon along highway 14. Rock slides
or debris flows can also be expected across roads in the burn area.

Please report flooding to your local law enforcement agency when you
can do so safely.

&&

LAT...LON 4073 10554 4078 10543 4069 10522 4053 10517
      4045 10542

$$

GIMMESTAD

384 
WGUS75 KBOU 102236
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
436 PM MDT THU AUG 10 2017

COC069-102246-
/O.EXP.KBOU.FF.W.0007.000000T0000Z-170810T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Larimer CO-
436 PM MDT THU AUG 10 2017

...THE FLASH FLOOD WARNING FOR EAST CENTRAL LARIMER COUNTY HAS
EXPIRED...

The heavy rain has ended. Flooding is no longer expected to pose a
threat. Drivers should watch out for possible damage on rural roads.

LAT...LON 4073 10554 4078 10543 4069 10522 4053 10517
      4045 10542

$$

GIMMESTAD

The office that day

Everything else NWS Denver/Boulder, CO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 10, 2:03 PM MDT	Special Weather Statement	BOU	Larimer	42 min
Aug 10, 2:28 PM MDT	Severe Thunderstorm Warning	BOU	Larimer	36 min
Aug 10, 3:02 PM MDT	Severe Thunderstorm Warning	BOU	Larimer, Weld	43 min
Aug 10, 3:07 PM MDT	Areal Flood Advisory	BOU	Larimer, Weld	83 min
Aug 10, 3:18 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Arapahoe, Denver, Jefferson	42 min
Aug 10, 3:54 PM MDT	Special Weather Statement	BOU	Weld	51 min
Aug 10, 3:54 PM MDT	Severe Thunderstorm Warning	BOU	Elbert, Lincoln	51 min
Aug 10, 4:01 PM MDT	Severe Thunderstorm Warning	BOU	Elbert, Lincoln	17 min
Aug 10, 4:06 PM MDT	Special Weather Statement	BOU	Denver	39 min
Aug 10, 4:13 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Arapahoe, Morgan, Weld	47 min
Aug 10, 4:23 PM MDT	Special Weather Statement	BOU	Lincoln	52 min
Aug 10, 4:37 PM MDT	Severe Thunderstorm Warning	BOU	Lincoln, Washington	38 min
Aug 10, 4:40 PM MDT	Areal Flood Advisory	BOU	Weld	65 min
Aug 10, 4:43 PM MDT	Severe Thunderstorm Warning	BOU	Lincoln	32 min
Aug 10, 4:48 PM MDT	Tornado Warning	BOU	Adams, Arapahoe	27 min
Aug 10, 5:07 PM MDT	Severe Thunderstorm Warning	BOU	Lincoln, Washington	25 min
Aug 10, 5:12 PM MDT	Areal Flood Advisory	BOU	Lincoln	93 min
Aug 10, 5:18 PM MDT	Special Weather Statement	BOU	Washington	27 min
Aug 10, 5:24 PM MDT	Severe Thunderstorm Warning	BOU	Lincoln	16 min

Nearby

Flash Flood Warnings in Colorado, 2017 Every flash flood warning in 2017

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.