Alaska, 2010

Flood in Alaska, July 23 to 24, 2010

July 23 to 24, 2010 · NWS AFG · 1 event in 1 county or zone

Just 10 days after a record flood impacted the Fortymile River and its tributaries another flood impacted the area. Water levels returned to pre-flood levels, however, occasional showers and saturated soils resulted in more significant rises than would normally be observed.

Where it happened

Every event with a place to put it. Tap one for its entry below.

  • Tornadoes
  • Tropical storms and surge
  • Floods
  • Wind
  • Hail
  • Winter weather
  • Heat and drought
  • Cold
  • Fire, smoke and dust
  • Marine and coastal
  • Other

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The toll

Deaths
0
Injuries
0
Property damage
$6.0 million
Crop damage
None recorded
Events
1

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS AFG wrote it up.

Just 10 days after a record flood impacted the Fortymile River and its tributaries another flood impacted the area. Water levels returned to pre-flood levels, however, occasional showers and saturated soils resulted in more significant rises than would normally be observed. Widespread rain fell across the Fortymile basin on the 22nd into the 23rd and produced between 1 and 2 inches of rain. A National Weather Service observer at the Walker Fork of the Fortymile River reported a stage only about one half foot lower than the previous flood. The Walker Fork campground was inundated with water and water was once again flowing across the Taylor Highway just north of the campground along with washouts about one mile north of the campground. A National Weather Service observer at O'Brien Creek reported a rise of nearly one foot per hour and a crest on the 23rd that was very close to the record crest observed on the 12th. The main channel of the Fortymile River at the Taylor Highway bridge crested approximately 7 feet below the level seen on the 12th, but still experienced a rise of nearly 13 feet. The State of Alaska declared the event a disaster with an estimate repair cost of $6 million.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Fairbanks, AK wrote its last area forecast discussion before the first event at Jul 22, 11:29 PM AKST, 6 hours 31 minutes earlier.

Area forecast discussion, Jul 22, 11:29 PM AKST, 6 hours 31 minutes before
NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
1229 AM AKDT FRI JUL 23 2010

.DISCUSSION...
CURRENT GFS/NAM RUNS AND GFS ENSEMBLE MEAN AGREE WELL THROUGH
00Z MON. UPPER LOW NOW OVER THE NORTHWEST CAPES WILL MOVE
SOUTHWARD IN A WOBBLY TRAJECTORY TO SOUTHEASTERN AKZ214/FAR
SOUTHWESTERN AKZ215 BY 12Z SUN. ASSOCIATED 996 MB SURFACE LOW
WILL BE DRAGGED SOUTHWARD BY THE UPPER LOW...FILLING TO AROUND
1003 MB BY 12Z SUN. WEAK UPPER RIDGING WILL PERSIST OVER THE
CENTRAL/EASTERN INTERIOR.

BAROCLINIC ZONE STRETCHING NORTH-SOUTH FROM THE WEST CENTRAL
BROOKS RANGE ACROSS THE INTERIOR WILL REMAIN STATIONARY AND
GRADUALLY WEAKEN DURING THE NEXT 24-36 HOURS. RAIN IN THE
BAROCLINIC ZONE WILL GRADUALLY TRANSITION TO SHOWERS AS THE ZONE
WEAKENS. OTHERWISE...SCATTERED SHOWERS CONTINUING IN WEST
COAST/WESTERN INTERIOR AREAS AS THE UPPER LOW TRACKS SOUTHWARD.
MODEL 24 HOUR QPFS THROUGH 12Z SAT INDICATE WIDESPREAD ADDITIONAL
RAINFALL OVER THE CENTRAL/WESTERN INTERIOR AND MUCH OF THE WEST
COAST...AMOUNTS GENERALLY FROM 0.10 TO 0.25 INCH WITH A FEW AREAS
OF 0.25 TO 0.5 INCH.

WEAK WORM-IN-THE-APPLE UPPER LOW NOW JUST NORTH OF MAYO
HAS BEEN TRACKING SLOWLY NORTHWARD DURING THE LAST 6 HOURS...AND
IS LIKELY TO REMAIN AN ENTITY AT LEAST THROUGH TONIGHT AND MAYBE
INTO SUN. THIS LOW WILL CONTINUE TO BOOST SHOWER ACTIVITY IN
AKZ224-EASTERN AKZ220. LOCAL AMOUNTS UP TO AN INCH POSSIBLE IN
THE NEXT 24 HOURS THROUGH 12Z SAT IN AREAS NEAR THE ALCAN BORDER.

THE MOST UNSTABLE AIR TODAY WILL BE IN INTERIOR AREAS NEAR THE
ALCAN BORDER...ALSO THE EASTERN BROOKS RANGE AND EASTERN INTERIOR
AREAS OF AKZ226. FOR SAT AND SUN...ISOLATED THUNDERSTORMS IN
AKZ206-AKZ218.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.FIRE WEATHER...
NONE

&&

.HYDROLOGY...
WIDESPREAD RAINS IN THE WESTERN INTERIOR SHOULD RESULT IN
SOME INCREASE IN LEVELS ON MANY RIVERS AND STREAMS...BUT
NO FLOODING IS EXPECTED. LOCALLY HEAVY SHOWERS POSSIBLE
TODAY AND TONIGHT IN AKZ224-EASTERN AKZ220.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
SMALL STREAM FLOOD ADVISORY IN EFFECT FOR THE EASTERN ALASKA
RANGE IN AKZ224-AKZ226 UNTIL 600 AM AKDT FRI. FLOOD ADVISORY IN
EFFECT FOR THE INMACHUK RIVER AT DEERING UNTIL 545 AM AKDT FRI.
WE ANTICIPATE CANCELING THESE ADVISORIES WITH THE MORNING
FORECAST ISSUANCE.

&&

RF JUL 10

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

1 flood. Local standard time, as filed.

Flood, Upr Tanana Vly Fortymile

When
July 23, 6:00 AM AKST to July 24, 10:00 AM AKST
Where
Upr Tanana Vly Fortymile County, Chicken
Cause
Heavy Rain
Property damage
$6.0 million
Reported by
River/Stream Gage
Coordinates
64.070, -141.950

What these are

Flood
Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Alaska in 2010Every state in 2010This day in weather historyWarnings in Alaska, July 2010

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 238672.