Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 71, NWS Flagstaff, AZ

July 21, 2021Coconino County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 21, 2021, 2:05 PM MST for Coconino County, Arizona. It was in force for 2 hr. 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
Jul 21, 2021, 2:05 PM MST (21:05 UTC)
Expired
Jul 21, 2021, 4:08 PM MST
In force
2 hr
Issued by
NWS Flagstaff, AZ
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Coconino County, AZ

The radar

The Flagstaff radar (KFSX), 107 km from the middle of the area, began a volume at 21:07 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

TimeReportWhereRemark
Jul 21, 3:00 PM MSTFLASH FLOOD1 Ssw Williams, AZFLOODED ROAD AT LEWIS STREET IN WILLIAMS.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 9.1 hours before the alert went out and 20 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, Flgstf/Belemont, AZ at 12:00Z on 2021-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 77 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Flgstf/Belemont, AZ at 12:00Z on 2021-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 20 square meters per square second.1939Sfc1 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
77 J/kg
Mixed-layer CIN
-129 J/kg
Mixed-layer LCL
1785 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
20 m²/s²
0-3 km storm-relative helicity
-11 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

852 
WGUS55 KFGZ 212105
FFWFGZ
AZC005-220015-
/O.NEW.KFGZ.FF.W.0071.210721T2105Z-210722T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
205 PM MST Wed Jul 21 2021

The National Weather Service in Flagstaff has issued a

* Flash Flood Warning for...
  Coconino County in north central Arizona...

* Until 515 PM MST.

* At 205 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. Additional rainfall amounts of 0.75 to 1.25 inches 
  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 low-water
           crossings, creeks, normally dry washes and roads.

* Some locations that will experience flash flooding include...
  Williams, Parks, Dogtown Lake Campground and Kaibab Lake 
  Campground.

This includes the following highways...
	Business Interstate 40 between mile markers 164 and 165.
	State Route 64 between mile markers 186 and 189.
	Interstate 40 between mile markers 164 and 178.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Flooding of washes and creeks will occur, some dirt roads will 
become muddy and impassable. Paved roads and underpasses could 
become flooded as well.

&&

LAT...LON 3535 11195 3524 11193 3523 11193 3516 11202
      3519 11216 3532 11221

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

EL
2 follow-up statements
732 
WGUS75 KFGZ 212143
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
243 PM MST Wed Jul 21 2021

AZC005-220015-
/O.CON.KFGZ.FF.W.0071.000000T0000Z-210722T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
243 PM MST Wed Jul 21 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 515 PM MST THIS 
AFTERNOON FOR COCONINO COUNTY...

At 243 PM MST, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. The heaviest rain has shifted westward 
over Williams. Between 1.25 and 2 inches of rain have fallen. 
Additional rainfall amounts of 0.25 to 0.75 inches 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 low-water crossings,
         creeks, normally dry washes and roads.

Some locations that will experience flash flooding include...
  Williams, Parks, Dogtown Lake Campground and Kaibab Lake 
  Campground.

This includes the following highways...
	Business Interstate 40 between mile markers 164 and 165.
	State Route 64 between mile markers 186 and 190.
	Interstate 40 between mile markers 164 and 178.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Flooding of washes and creeks will occur, some dirt roads will 
become muddy and impassable. Paved roads and underpasses could 
become flooded as well.

&&

LAT...LON 3535 11195 3524 11193 3523 11193 3516 11202
      3519 11216 3532 11221

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

EL
670 
WGUS75 KFGZ 212308
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
408 PM MST Wed Jul 21 2021

AZC005-212318-
/O.CAN.KFGZ.FF.W.0071.000000T0000Z-210722T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
408 PM MST Wed Jul 21 2021

...FLASH FLOOD WARNING BETWEEN PARKS AND WILLIAMS ALONG I-40 IN 
COCONINO COUNTY IS CANCELLED...

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

LAT...LON 3535 11195 3524 11193 3523 11193 3516 11202
      3519 11216 3532 11221

$$

EL

The office that day

Everything else NWS Flagstaff, AZ issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 20, 6:16 PM MSTSpecial Weather StatementFGZ29 min
Jul 20, 7:32 PM MSTSevere Thunderstorm WarningFGZNavajo28 min
Jul 20, 7:55 PM MSTFlash Flood Warning Considerable damage threatFGZNavajo2 hr
Jul 20, 8:33 PM MSTFlash Flood Warning Considerable damage threatFGZNavajo117 min
Jul 21, 12:17 AM MSTFlash Flood Warning Considerable damage threatFGZGila118 min
Jul 21, 2:38 AM MSTFlash Flood WatchFGZApache, Coconino, Gila, Navajo, Yavapai5 days
Jul 21, 10:19 AM MSTSpecial Weather StatementFGZYavapai26 min
Jul 21, 10:48 AM MSTFlash Flood Warning Considerable damage threatFGZYavapai2 hr
Jul 21, 12:03 PM MSTSpecial Weather StatementFGZYavapai42 min
Jul 21, 12:13 PM MSTFlash Flood Warning Considerable damage threatFGZYavapai56 min
Jul 21, 12:20 PM MSTFlash Flood Warning Considerable damage threatFGZYavapai114 min
Jul 21, 12:35 PM MSTSpecial Weather StatementFGZ40 min
Jul 21, 12:47 PM MSTFlash Flood Warning Considerable damage threatFGZCoconino118 min
Jul 21, 12:54 PM MSTSpecial Weather StatementFGZ36 min
Jul 21, 1:06 PM MSTFlash Flood Warning Considerable damage threatFGZCoconino92 min
Jul 21, 1:24 PM MSTFlash Flood Warning Considerable damage threatFGZCoconino110 min
Jul 21, 1:27 PM MSTFlash Flood Warning Considerable damage threatFGZYavapai74 min
Jul 21, 1:57 PM MSTSpecial Weather StatementFGZYavapai48 min
Jul 21, 2:01 PM MSTAreal Flood AdvisoryFGZYavapai119 min
Jul 21, 2:22 PM MSTAreal Flood AdvisoryFGZCoconino3 hr
Jul 21, 2:30 PM MSTSpecial Weather StatementFGZ45 min
Jul 21, 2:36 PM MSTFlash Flood Warning Considerable damage threatFGZYavapai54 min
Jul 21, 2:53 PM MSTFlash Flood Warning Considerable damage threatFGZCoconino82 min
Jul 21, 2:57 PM MSTFlash Flood Warning Considerable damage threatFGZYavapai60 min
Jul 21, 2:59 PM MSTFlash Flood Warning Considerable damage threatFGZYavapai60 min
Jul 21, 3:21 PM MSTSevere Thunderstorm WarningFGZCoconino26 min
Jul 21, 3:34 PM MSTFlash Flood Warning Considerable damage threatFGZCoconino98 min
Jul 21, 3:49 PM MSTFlash Flood Warning Considerable damage threatFGZYavapai3 hr
Jul 21, 4:35 PM MSTFlash Flood Warning Considerable damage threatFGZCoconino115 min

Nearby

Flash Flood Warnings in Arizona, 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.