Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 103, NWS Flagstaff, AZ

July 25, 2021Navajo County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 25, 2021, 12:05 PM MDT for Navajo County, Arizona. It was in force for 11 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, 2021, 12:05 PM MDT (18:05 UTC)
Expired: Jul 25, 2021, 11:15 PM MDT
In force: 11 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), 109 km from the middle of the area, began a volume at 18:05 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, 6.1 hours before the alert went out and 182 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: 4 J/kg
Mixed-layer CIN: -19 J/kg
Mixed-layer LCL: 803 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: -30 m²/s²
0-3 km storm-relative helicity: 25 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

652 
WGUS55 KFGZ 251805
FFWFGZ
AZC017-252115-
/O.NEW.KFGZ.FF.W.0103.210725T1805Z-210725T2115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
1105 AM MST Sun Jul 25 2021

The National Weather Service in Flagstaff has issued a

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

* Until 215 PM MST.

* At 1102 AM MST, emergency management reported run off from several 
  days of heavy rainfall creating flooding issues in the area. 
  Additional shower and thunderstorm activity today will produce 
  rainfall amounts of 0.5 to 1 inch. Flash flooding is ongoing or 
  expected to begin shortly.

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

  SOURCE...Emergency management reported.

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

* Some locations that will experience flash flooding include...
  Taylor, Shumway, Snowflake and White Mountain Lake.

This includes the following highways...
	State Route 77 between mile markers 348 and 364.
	State Route 277 between mile markers 331 and 336.

This includes the following streams and drainages...
  Canal, The, Cottonwood Wash, Linden Draw, Concho Flat Wash, Silver 
  Creek, Rocky Arroyo, Dodson Wash, Hay Hollow Draw and Show Low 
  Creek.

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 3460 10997 3444 10985 3431 11009 3451 11019

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

$$

TPS

5 follow-up statements

352 
WGUS55 KFGZ 252054
FFWFGZ
AZC017-260515-
/O.EXT.KFGZ.FF.W.0103.000000T0000Z-210726T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
154 PM MST Sun Jul 25 2021

The National Weather Service in Flagstaff has extended the

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

* Until 1015 PM MST Sunday.

* At 153 PM MST, emergency management reported run off from several 
  days of heavy rainfall creating flooding issues in the area. 
  Additional shower and thunderstorm activity through this evening 
  will produce rainfall amounts of 0.5 to 1 inch. Flash flooding is 
  ongoing or expected to begin shortly.

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

  SOURCE...Emergency management reported.

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

* Some locations that will experience flash flooding include...
  Taylor, Shumway, Snowflake and White Mountain Lake.

This includes the following highways...
	State Route 77 between mile markers 348 and 364.
	State Route 277 between mile markers 331 and 336.

This includes the following streams and drainages...
  Canal, The, Cottonwood Wash, Linden Draw, Concho Flat Wash, Silver 
  Creek, Rocky Arroyo, Dodson Wash, Hay Hollow Draw and Show Low 
  Creek.

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 3460 10997 3444 10985 3431 11009 3451 11019

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

$$

TPS

592 
WGUS75 KFGZ 252123
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
223 PM MST Sun Jul 25 2021

AZC017-260515-
/O.CON.KFGZ.FF.W.0103.000000T0000Z-210726T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Navajo AZ-
223 PM MST Sun Jul 25 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1015 PM MST THIS 
EVENING FOR NAVAJO COUNTY...

At 218 PM MST, emergency management reported there is the potential 
for the Millet Swale Levee to fail. This could produce impacts 3 
miles downstream of the Millet Swale Reservoir near Taylor.

HAZARD...Life-threatening flash flooding.

SOURCE...Emergency management reported.

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

Some locations that could experience flash flooding include...
  Taylor, Shumway, Snowflake and White Mountain Lake.

This includes the following highways...
	State Route 77 between mile markers 348 and 364.
	State Route 277 between mile markers 331 and 336.

This includes the following streams and drainages...
  Cottonwood Wash, Linden Draw, Concho Flat Wash, Silver Creek, 
  Rocky Arroyo, Dodson Wash, Hay Hollow Draw and Show Low Creek.

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 3460 10997 3444 10985 3431 11009 3451 11019

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

$$

TPS

729 
WGUS75 KFGZ 260129
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
629 PM MST Sun Jul 25 2021

AZC017-260515-
/O.CON.KFGZ.FF.W.0103.000000T0000Z-210726T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Navajo AZ-
629 PM MST Sun Jul 25 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1015 PM MST THIS 
EVENING FOR NAVAJO COUNTY...

At 600 PM MST, emergency management reported that the Millet Swale 
Levee has failed. Impacts are expected 3 miles downstream of the 
Millet Swale Reservoir near Taylor.

HAZARD...Life-threatening flash flooding.

SOURCE...Emergency management reported.

IMPACT...Flash flooding of low-water crossings and Silver Creek
         is expected. At this time only minor flooding of
         residential and commercial areas in Taylor and Snowflake
         is anticipated as per Navajo County Emergency
         Management.

Some locations that will experience flash flooding include...
  Taylor and Snowflake.

This includes the following highways...
	State Route 77 between mile markers 348 and 364.
	State Route 277 between mile markers 331 and 336.

This includes the following streams and drainages...
Silver Creek.

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 3460 10997 3444 10985 3431 11009 3451 11019

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

$$

McCollum

293 
WGUS75 KFGZ 260145
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
645 PM MST Sun Jul 25 2021

AZC017-260515-
/O.CON.KFGZ.FF.W.0103.000000T0000Z-210726T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Navajo AZ-
645 PM MST Sun Jul 25 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1015 PM MST THIS 
EVENING FOR NAVAJO COUNTY...

At 636 PM MST, emergency management reported that the Millet Swale 
Levee has failed. Impacts are expected 3 miles downstream of the 
Millet Swale Reservoir near Taylor.

HAZARD...Flash flooding.

SOURCE...Emergency management reported.

IMPACT...Flash flooding of low-water crossings and Silver Creek
         is expected. At this time minor flooding of residential
         and commercial areas in Taylor and Snowflake is
         anticipated as per Navajo County Emergency Management.
         Silver Creek is forecast to rise 1.2 feet (5,257 CFS)
         above flood stage in Taylor and 1.1 feet (4000 CFS)
         above flood stage in Snowflake.

Some locations that will experience flash flooding include...
  Taylor and Snowflake.

This includes the following highways...
	State Route 77 between mile markers 348 and 364.
	State Route 277 between mile markers 331 and 336.

This includes the following streams and drainages...
  Silver Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...




&&

LAT...LON 3460 10997 3444 10985 3431 11009 3451 11019

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

$$

McCollum

812 
WGUS75 KFGZ 260513
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
1013 PM MST Sun Jul 25 2021

AZC017-260523-
/O.EXP.KFGZ.FF.W.0103.000000T0000Z-210726T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Navajo AZ-
1013 PM MST Sun Jul 25 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 1015 PM MST THIS EVENING FOR 
NAVAJO COUNTY...

The Flash Flood Warning for the Miller Swale Levee failure has 
ended. Earlier this evening the levee gave way but Navajo County 
Emergency Management is reporting that most of the water was flowing 
across the surrounding landscape with no impacts being reported in 
Taylor or Snowflake. As of 800 pm, the Swale Reservoir had mostly 
drained so a further threat of flash flooding is not anticipated.

A Flash Flood Watch remains in effect until 1200 AM MST for portions 
of east central Arizona, north central Arizona, northeast Arizona 
and west central Arizona.

LAT...LON 3460 10997 3444 10985 3431 11009 3451 11019

$$

McCollum

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 24, 6:30 PM MDT	Severe Thunderstorm Warning	FGZ	Coconino, Navajo	30 min
Jul 24, 8:12 PM MDT	Areal Flood Advisory	FGZ	Coconino, Navajo	3 hr
Jul 24, 8:50 PM MDT	Areal Flood Advisory	FGZ	Coconino	3 hr
Jul 24, 9:49 PM MDT	Areal Flood Advisory	FGZ	Coconino, Yavapai	3 hr
Jul 24, 10:32 PM MDT	Areal Flood Advisory	FGZ	Yavapai	3 hr
Jul 24, 11:47 PM MDT	Areal Flood Warning	FGZ	Navajo	6 hr
Jul 25, 12:06 AM MDT	Areal Flood Advisory	FGZ	Apache, Coconino, Navajo	12 hr
Jul 25, 3:30 AM MDT	Areal Flood Advisory	FGZ	Coconino, Navajo	24 hr
Jul 25, 3:51 AM MDT	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	6 hr
Jul 25, 5:58 AM MDT	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 25, 10:15 AM MDT	Areal Flood Warning	FGZ	Apache, Coconino, Navajo	13 hr
Jul 25, 1:39 PM MDT	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Gila, Yavapai	3 hr
Jul 25, 2:51 PM MDT	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Jul 25, 3:27 PM MDT	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Yavapai	108 min
Jul 25, 3:52 PM MDT	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 25, 4:28 PM MDT	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.