Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 48, NWS Flagstaff, AZ

July 18, 2021Navajo County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 18, 2021, 5:32 PM MDT for Navajo County, Arizona. It was in force for 4 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 18, 2021, 5:32 PM MDT (23:32 UTC)
Expired: Jul 18, 2021, 9:45 PM MDT
In force: 4 hr
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Navajo County, AZ

The radar

The Flagstaff radar (KFSX), 127 km from the middle of the area, began a volume at 23:35 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

Time	Report	Where	Remark
Jul 18, 8:32 PM MDT	FLASH FLOOD	6 Nw Castle Butte, AZ	LAW ENFORCEMENT IN DILKON REPORTED ONGOING FLOODING ALONG SR 87 AND ROUTE 60 IN DILKON.

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, 11.5 hours before the alert went out and 137 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: 191 J/kg
Mixed-layer CIN: -101 J/kg
Mixed-layer LCL: 1511 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 14 m²/s²
0-3 km storm-relative helicity: 46 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

746 
WGUS55 KFGZ 182332
FFWFGZ
AZC017-190245-
/O.NEW.KFGZ.FF.W.0048.210718T2332Z-210719T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
432 PM MST Sun Jul 18 2021

The National Weather Service in Flagstaff has issued a

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

* Until 745 PM MST.

* At 431 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 1.5 inches of 
  rain have fallen. Additional rainfall amounts of 0.5 to 1 inch 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...
  Coyote Wash, Cedar Springs, Dilkon, Hopi Reservation and Navajo 
  Reservation.

This includes the following highways...
	State Route 87 between mile markers 374 and 382.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 3558 11031 3546 11014 3536 11023 3534 11045
      3544 11044

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

$$

EL

5 follow-up statements

752 
WGUS75 KFGZ 190003
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
503 PM MST Sun Jul 18 2021

AZC017-190245-
/O.CON.KFGZ.FF.W.0048.000000T0000Z-210719T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Navajo AZ-
503 PM MST Sun Jul 18 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 745 PM MST THIS 
EVENING FOR NAVAJO COUNTY...

At 502 PM MST, the heavy rain in the warned area has decreased in 
intensity, however flooding can still occur. Between 1 and 1.5 
inches of rain have fallen.

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...
  Cedar Springs, Dilkon, Hopi Reservation and Navajo Reservation.

This includes the following highways...
	State Route 87 between mile markers 374 and 381.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 3558 11031 3546 11014 3536 11023 3534 11045
      3544 11044

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

$$

EL

879 
WGUS75 KFGZ 190047
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
547 PM MST Sun Jul 18 2021

AZC017-190245-
/O.CON.KFGZ.FF.W.0048.000000T0000Z-210719T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Navajo AZ-
547 PM MST Sun Jul 18 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 745 PM MST THIS 
EVENING FOR NAVAJO COUNTY...

At 545 PM MST, the heavy rainfall from thunderstorms has decreased 
in intensity, however flooding can still occur as water drains. 
Between 1.25 and 1.75 inches of rain have fallen.

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...
  Cedar Springs, Dilkon and Navajo Reservation.

This includes the following highways...
	State Route 87 between mile markers 375 and 381.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 3547 11040 3547 11030 3538 11030 3534 11045
      3544 11044

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

$$

EL

632 
WGUS75 KFGZ 190150
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
650 PM MST Sun Jul 18 2021

AZC017-190245-
/O.CON.KFGZ.FF.W.0048.000000T0000Z-210719T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Navajo AZ-
650 PM MST Sun Jul 18 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 745 PM MST THIS 
EVENING FOR NAVAJO COUNTY...

At 648 PM MST, Doppler radar indicated light rain continues near 
Dilkon. The heavy rain threat has ended. Between 1.25 and 1.75 
inches of rain have fallen. Additional rainfall amounts up to 0.25 
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...
  Coyote Wash, Cedar Springs, Dilkon, Hopi Reservation and Navajo 
  Reservation.

This includes the following highways...
	State Route 87 between mile markers 375 and 381.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 3547 11040 3547 11030 3538 11030 3534 11045
      3544 11044

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

$$

TPS

299 
WGUS55 KFGZ 190231
FFWFGZ
AZC017-190345-
/O.EXT.KFGZ.FF.W.0048.000000T0000Z-210719T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
731 PM MST Sun Jul 18 2021

The National Weather Service in Flagstaff has extended the

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

* Until 845 PM MST.

* At 728 PM MST, local law enforcement reported ongoing flooding on 
  State Route 87 and Route 60 in the Dilkon area. The heavy rain 
  threat has ended, but flooding will continue over the next couple 
  hours. Between 1.25 and 1.75 inches of rain have fallen.

  HAZARD...Life-threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Law enforcement reported.

  IMPACT...Life-threatening flash flooding of low-water
           crossings, creeks, normally dry washes and roads.

* Some locations that will experience flash flooding include...
  Coyote Wash, Cedar Springs, Dilkon, Hopi Reservation and Navajo 
  Reservation.

This includes the following highways...
	State Route 87 between mile markers 375 and 381.
    Route 60.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

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 3547 11040 3547 11030 3538 11030 3534 11045
      3544 11044

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

TPS

995 
WGUS75 KFGZ 190336
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
836 PM MST Sun Jul 18 2021

AZC017-190346-
/O.EXP.KFGZ.FF.W.0048.000000T0000Z-210719T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Navajo AZ-
836 PM MST Sun Jul 18 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 845 PM MST THIS EVENING FOR 
NAVAJO COUNTY...

Heavy rainfall has ended near Dilkon and flood waters will continue 
to recede. Please continue to heed remaining road closures.

LAT...LON 3547 11040 3547 11030 3538 11030 3534 11045
      3544 11044

$$

TPS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 18, 11:58 AM MDT	Severe Thunderstorm Warning	FGZ	Yavapai	32 min
Jul 18, 12:14 PM MDT	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 18, 1:16 PM MDT	Severe Thunderstorm Warning	FGZ	Coconino	29 min
Jul 18, 2:03 PM MDT	Flash Flood Warning Considerable damage threat	FGZ	Navajo	3 hr
Jul 18, 2:08 PM MDT	Special Weather Statement	FGZ		37 min
Jul 18, 2:34 PM MDT	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Jul 18, 3:12 PM MDT	Severe Thunderstorm Warning	FGZ	Gila, Navajo	33 min
Jul 18, 3:18 PM MDT	Severe Thunderstorm Warning	FGZ	Gila	42 min
Jul 18, 3:31 PM MDT	Areal Flood Advisory	FGZ	Coconino	100 min
Jul 18, 3:33 PM MDT	Severe Thunderstorm Warning	FGZ	Navajo	42 min
Jul 18, 3:53 PM MDT	Flash Flood Warning Considerable damage threat	FGZ	Gila, Navajo	102 min
Jul 18, 4:02 PM MDT	Flash Flood Warning Considerable damage threat	FGZ	Coconino	108 min
Jul 18, 4:47 PM MDT	Severe Thunderstorm Warning	FGZ	Gila	43 min
Jul 18, 4:54 PM MDT	Special Weather Statement	FGZ		51 min
Jul 18, 5:10 PM MDT	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	51 min
Jul 18, 5:59 PM MDT	Severe Thunderstorm Warning	FGZ	Gila, Yavapai	46 min

Nearby

Flash Flood Warnings in Arizona, 2021 Every 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.