Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 213, NWS Flagstaff, AZ

August 18, 2021Coconino County, Yavapai County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Aug 18, 2021, 5:17 PM MST for Coconino County, Yavapai County, Arizona. It was in force for 4 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: Aug 18, 2021, 5:17 PM MST (00:17 UTC)
Expired: Aug 18, 2021, 9:15 PM MST
In force: 4 hr
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Coconino County, AZ, Yavapai County, AZ

The radar

The Flagstaff radar (KFSX), 97 km from the middle of the area, began a volume at 00:17 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 00:00Z, 0.3 hours before the alert went out and 36 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: 605 J/kg
Mixed-layer CIN: -17 J/kg
Mixed-layer LCL: 745 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 109 m²/s²
0-3 km storm-relative helicity: 108 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.8

Open this sounding in Storm Lab

The text

As transmitted.

187 
WGUS55 KFGZ 190017
FFWFGZ
AZC005-025-190115-
/O.NEW.KFGZ.FF.W.0213.210819T0017Z-210819T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
517 PM MST Wed Aug 18 2021

The National Weather Service in Flagstaff has issued a

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

* Until 615 PM MST.

* At 517 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.25 and 2.5 inches of 
  rain have fallen. Additional rainfall amounts of 0.75 to 1.5 
  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...
  Perkinsville, White Horse Lake Campground and Raymond Boy Scout 
  Camp.

This includes the following swimming holes...
Sycamore Falls, Lower Sycamore Falls "The Golden Pond", Paradise 
Forks and Parsons Spring along Sycamore 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.

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 3508 11224 3520 11204 3509 11188 3495 11199
      3485 11208 3493 11230

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

$$

DB

3 follow-up statements

191 
WGUS55 KFGZ 190103
FFWFGZ
AZC005-025-190315-
/O.EXT.KFGZ.FF.W.0213.000000T0000Z-210819T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
603 PM MST Wed Aug 18 2021

The National Weather Service in Flagstaff has extended the

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

* Until 815 PM MST.

* At 602 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Heavy rain continues across the 
  northern portion of the warning. Between 2 and 3.5 inches of rain 
  have fallen across the area today. Additional rainfall amounts of 
  0.75 to 1.5 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...
  Perkinsville, White Horse Lake Campground and Raymond Boy Scout 
  Camp.

This includes the following swimming holes...
Sycamore Falls, Lower Sycamore Falls "The Golden Pond", Paradise 
Forks and Parsons Spring along Sycamore 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.

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 3508 11224 3520 11204 3509 11188 3495 11199
      3485 11208 3493 11230

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

$$

ET

029 
WGUS55 KFGZ 190310
FFWFGZ
AZC005-025-190415-
/O.EXT.KFGZ.FF.W.0213.000000T0000Z-210819T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
810 PM MST Wed Aug 18 2021

The National Weather Service in Flagstaff has extended the

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

* Until 915 PM MST.

* At 809 PM MST, Heavy rainfall fell across the warned area earlier 
  today. Flash flooding is ongoing across the warned area in 
  Sycamore Creek.

  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...
  Perkinsville, White Horse Lake Campground and Raymond Boy Scout 
  Camp.

This includes the following swimming holes...
Sycamore Falls, Lower Sycamore Falls "The Golden Pond", Paradise 
Forks and Parsons Spring along Sycamore 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.

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 3508 11224 3520 11204 3509 11188 3495 11199
      3485 11208 3493 11230

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

$$

ET

389 
WGUS75 KFGZ 190412
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
912 PM MST Wed Aug 18 2021

AZC005-025-190422-
/O.EXP.KFGZ.FF.W.0213.000000T0000Z-210819T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-Yavapai AZ-
912 PM MST Wed Aug 18 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 915 PM MST THIS EVENING FOR 
COCONINO AND YAVAPAI COUNTIES...

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

A Flash Flood Watch remains in effect until 1100 PM MST for portions 
of east central Arizona, north central Arizona, northeast Arizona 
and west central Arizona.

A Flash Flood Watch remains in effect until 1100 PM MST for a 
portion of west central Arizona.

LAT...LON 3508 11224 3520 11204 3509 11188 3495 11199
      3485 11208 3493 11230

$$

ET

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 18, 5:13 PM MST	Flash Flood Warning	FGZ	Yavapai	3 hr
Aug 18, 5:31 PM MST	Special Weather Statement	FGZ	Yavapai	29 min
Aug 18, 5:43 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	23 min
Aug 18, 7:59 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Gila	4 hr
Aug 18, 8:08 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	6 hr
Aug 18, 10:41 PM MST	Areal Flood Warning	FGZ	Gila, Yavapai	10 hr
Aug 18, 11:56 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	8 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.