Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 36, NWS Flagstaff, AZ

July 16, 2021Coconino County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 16, 2021, 11:56 AM MST for Coconino County, Arizona. It was in force for 3 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 16, 2021, 11:56 AM MST (18:56 UTC)
Expired
Jul 16, 2021, 3:00 PM MST
In force
3 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), 144 km from the middle of the area, began a volume at 18:57 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

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 6.9 hours before the alert went out and 72 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 2021-07-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 487 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 2021-07-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 77 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
487 J/kg
Mixed-layer CIN
-59 J/kg
Mixed-layer LCL
1090 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
77 m²/s²
0-3 km storm-relative helicity
88 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

989 
WGUS55 KFGZ 161856
FFWFGZ
AZC005-162200-
/O.NEW.KFGZ.FF.W.0036.210716T1856Z-210716T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
1156 AM MST Fri Jul 16 2021

The National Weather Service in Flagstaff has issued a

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

* Until 300 PM MST.

* At 1154 AM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen in the last 45-50 minutes. 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...
  Cameron and Navajo Reservation.

This includes the following highways...
	U.S. Highway 89 between mile markers 459 and 466.
	State Route 64 between mile markers 289 and 295.

This includes the following streams and drainages...
  Little Colorado River, Tappan Wash, Cedar Wash, Needmore Wash and 
  Burro Canyon Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Move to higher ground now. Act quickly to protect your life.

In hilly or mountainous terrain, there are many low water crossings 
which will become dangerous in heavy rain. Do not attempt to cross 
flooded roads. Find an alternate route.

Remain alert for flooding even in locations not receiving rain. 
Normally dry washes, slot canyons and creeks can become raging 
killer currents in a matter of minutes, even from distant rainfall.

&&

LAT...LON 3585 11168 3588 11161 3591 11148 3587 11142
      3585 11138 3577 11136 3575 11162

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

$$

ET
3 follow-up statements
618 
WGUS75 KFGZ 161938
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
1238 PM MST Fri Jul 16 2021

AZC005-162200-
/O.CON.KFGZ.FF.W.0036.000000T0000Z-210716T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
1238 PM MST Fri Jul 16 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 3 PM MST THIS 
AFTERNOON FOR COCONINO COUNTY...

At 1237 PM MST, Doppler radar indicated a nearly stationary storm 
producing heavy rain across the warned area. Moderate to heavy rain 
continues at this time. Between 2 and 3 inches of rain have fallen. 
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...
  Cameron and Navajo Reservation.

This includes the following highways...
	U.S. Highway 89 between mile markers 459 and 466.
	State Route 64 between mile markers 289 and 295.

This includes the following streams and drainages...
  Little Colorado River, Tappan Wash, Cedar Wash, Needmore Wash and 
  Burro Canyon Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Move to higher ground now. Act quickly to protect your life.

In hilly or mountainous terrain, there are many low water crossings 
which will become dangerous in heavy rain. Do not attempt to cross 
flooded roads. Find an alternate route.

Remain alert for flooding even in locations not receiving rain. 
Normally dry washes, slot canyons and creeks can become raging 
killer currents in a matter of minutes, even from distant rainfall.

&&

LAT...LON 3585 11168 3588 11161 3591 11148 3587 11142
      3585 11138 3577 11136 3575 11162

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

$$

ET
077 
WGUS75 KFGZ 162105
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
205 PM MST Fri Jul 16 2021

AZC005-162200-
/O.CON.KFGZ.FF.W.0036.000000T0000Z-210716T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
205 PM MST Fri Jul 16 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 3 PM MST THIS 
AFTERNOON FOR COCONINO COUNTY...

At 204 PM MST, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area earlier today. Rain has ended now. Flash 
flooding likely to continue over the next hour.

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...
  Cameron and Navajo Reservation.

This includes the following highways...
	U.S. Highway 89 between mile markers 459 and 466.
	State Route 64 between mile markers 289 and 295.

This includes the following streams and drainages...
  Little Colorado River, Tappan Wash, Cedar Wash, Needmore Wash and 
  Burro Canyon Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Move to higher ground now. Act quickly to protect your life.

In hilly or mountainous terrain, there are many low water crossings 
which will become dangerous in heavy rain. Do not attempt to cross 
flooded roads. Find an alternate route.

Remain alert for flooding even in locations not receiving rain. 
Normally dry washes, slot canyons and creeks can become raging 
killer currents in a matter of minutes, even from distant rainfall.

&&

LAT...LON 3585 11168 3588 11161 3591 11148 3587 11142
      3585 11138 3577 11136 3575 11162

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

$$

ET
859 
WGUS75 KFGZ 162150
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
250 PM MST Fri Jul 16 2021

AZC005-162200-
/O.EXP.KFGZ.FF.W.0036.000000T0000Z-210716T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
250 PM MST Fri Jul 16 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 3 PM MST THIS AFTERNOON FOR 
COCONINO COUNTY...

Flooding is no longer expected to pose a threat. Please continue to 
heed remaining road closures.

LAT...LON 3585 11168 3588 11161 3591 11148 3587 11142
      3585 11138 3577 11136 3575 11162

$$

ET

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 15, 5:20 PM MSTAreal Flood AdvisoryFGZYavapai115 min
Jul 15, 6:33 PM MSTSevere Thunderstorm WarningFGZYavapai27 min
Jul 15, 6:55 PM MSTAreal Flood AdvisoryFGZYavapai3 hr
Jul 15, 8:21 PM MSTFlash Flood Warning Considerable damage threatFGZYavapai114 min
Jul 16, 12:03 PM MSTAreal Flood AdvisoryFGZYavapai2 hr
Jul 16, 12:36 PM MSTAreal Flood AdvisoryFGZCoconino2 hr
Jul 16, 12:52 PM MSTSpecial Weather StatementFGZ23 min
Jul 16, 1:16 PM MSTSevere Thunderstorm WarningFGZCoconino29 min
Jul 16, 1:20 PM MSTFlash Flood Warning Considerable damage threatFGZCoconino115 min
Jul 16, 1:24 PM MSTSevere Thunderstorm WarningFGZGila, Navajo51 min
Jul 16, 1:44 PM MSTSpecial Weather StatementFGZ46 min
Jul 16, 2:13 PM MSTSevere Thunderstorm WarningFGZGila, Navajo32 min
Jul 16, 2:25 PM MSTAreal Flood AdvisoryFGZCoconino3 hr
Jul 16, 2:59 PM MSTFlash Flood Warning Considerable damage threatFGZCoconino61 min
Jul 16, 3:14 PM MSTSpecial Weather StatementFGZ31 min
Jul 16, 3:43 PM MSTSevere Thunderstorm WarningFGZCoconino, Yavapai32 min
Jul 16, 4:18 PM MSTSevere Thunderstorm WarningFGZYavapai12 min
Jul 16, 4:34 PM MSTSevere Thunderstorm WarningFGZGila41 min
Jul 16, 4:41 PM MSTFlash Flood Warning Considerable damage threatFGZGila3 hr
Jul 16, 4:48 PM MSTSevere Thunderstorm WarningFGZCoconino, Gila20 min
Jul 16, 4:59 PM MSTSevere Thunderstorm WarningFGZGila, Yavapai15 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.