Alert archive / Colorado / Flash Flood Warnings in 2018

Flash Flood Warning 21, NWS Grand Junction, CO

July 25, 20184 counties in Colorado

NWS Grand Junction, CO issued this flash flood warning at Jul 25, 2018, 12:53 PM MDT for 4 counties in Colorado. It was in force for 5 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 25, 2018, 12:53 PM MDT (18:53 UTC)
Expired
Jul 25, 2018, 5:45 PM MDT
In force
5 hr
Issued by
NWS Grand Junction, CO
Area
Storm-based polygon
Flood severity
None

Counties Dolores County, CO, La Plata County, CO, Montezuma County, CO, San Juan County, CO

The radar

The Grand Junction radar (KGJX), 176 km from the middle of the area, began a volume at 18:54 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

Grand Junction, CO (KGJT), launched 12:00Z, 6.9 hours before the alert went out and 189 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-pSkew-T log-p diagram, Grand Junction, CO at 12:00Z on 2018-07-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 15 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Grand Junction, CO at 12:00Z on 2018-07-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 101 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
15 J/kg
Mixed-layer CIN
-274 J/kg
Mixed-layer LCL
2612 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
101 m²/s²
0-3 km storm-relative helicity
175 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

978 
WGUS55 KGJT 251853
FFWGJT
COC033-067-083-111-252345-
/O.NEW.KGJT.FF.W.0021.180725T1853Z-180725T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Grand Junction CO
1253 PM MDT WED JUL 25 2018

The National Weather Service in Grand Junction has issued a

* Flash Flood Warning for...
  Eastern Dolores County in southwestern Colorado...
  Northeastern Montezuma County in southwestern Colorado...
  Southwestern San Juan County in southwestern Colorado...
  North central La Plata County in southwestern Colorado...

* Until 545 PM MDT.

* At 1250 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the 416 fire burn scar. Flash flooding is 
  expected to begin shortly. 

* Some locations that will experience flooding include...
  Durango, Tacoma, Rockwood, Hermosa and Trimble. 

Excessive rainfall over the burn scar will result in debris flow 
moving through the Hermosa Creek and Tripp Gulch Drainages. The 
debris flow can consist of rock, mud, vegetation and other loose 
materials.

This includes U.S. Highway 550 in Colorado between mile markers 25
and 48 as well as County Road 250.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

LAT...LON 3762 10775 3732 10779 3731 10789 3741 10793
      3746 10805 3760 10803 3765 10797

$$

MDA
2 follow-up statements
151 
WGUS75 KGJT 252048
FFSGJT

Flash Flood Statement
National Weather Service Grand Junction CO
248 PM MDT WED JUL 25 2018

COC033-067-083-111-252345-
/O.CON.KGJT.FF.W.0021.000000T0000Z-180725T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Dolores CO-Montezuma CO-San Juan CO-La Plata CO-
248 PM MDT WED JUL 25 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 545 PM MDT FOR
EASTERN DOLORES...NORTHEASTERN MONTEZUMA...SOUTHWESTERN SAN JUAN AND
NORTH CENTRAL LA PLATA COUNTIES...

At 243 PM MDT, Doppler radar indicated thunderstorms producing heavy 
rain across the 416 Fire burn scar area. Flash flooding was reported 
by emergency management along Tripp Creek Gulch with a 4 to 5 foot 
wall of debris flowing down Tripp Gulch across County Road 203 and 
into yards of homes along Tripp Creek Road. Flash flooding is 
expected to continue as heavy rain continues to fall within the 
warned area.

Excessive rainfall over the burn scar will result in debris flow 
moving through the Hermosa Creek Drainage and Tripp Creek Gulch 
Drainage. The debris flow can consist of rock, mud, vegetation and 
other loose materials.

Some locations that will experience flooding include...
Durango, Tacoma, Rockwood, Hermosa and Trimble. 

This includes U.S. Highway 550 in Colorado between mile markers 25
and 48 and areas along CR 203 and 250. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

LAT...LON 3762 10775 3732 10779 3731 10789 3741 10793
      3746 10805 3760 10803 3765 10797

$$

MDA
429 
WGUS75 KGJT 252339
FFSGJT

Flash Flood Statement
National Weather Service Grand Junction CO
539 PM MDT WED JUL 25 2018

COC033-067-083-111-252349-
/O.EXP.KGJT.FF.W.0021.000000T0000Z-180725T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Dolores CO-Montezuma CO-San Juan CO-La Plata CO-
539 PM MDT WED JUL 25 2018

...THE FLASH FLOOD WARNING FOR EASTERN DOLORES...NORTHEASTERN
MONTEZUMA...SOUTHWESTERN SAN JUAN AND NORTH CENTRAL LA PLATA COUNTIES
WILL EXPIRE AT 545 PM MDT...

The heavy rain has ended. Flood waters have receded. Flooding is no
longer expected to pose a threat. Please continue to heed any
remaining road closures.

LAT...LON 3762 10775 3732 10779 3731 10789 3741 10793
      3746 10805 3760 10803 3765 10797

$$

NL

The office that day

Everything else NWS Grand Junction, CO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 25, 2:34 PM MDTAreal Flood AdvisoryGJTSan Miguel3 hr

Nearby

Flash Flood Warnings in Colorado, 2018Every flash flood warning in 2018

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.