Alaska, 2023

Flood in Alaska, June 7 to 14, 2023

June 7 to 14, 2023 · NWS AFG · 1 event in 1 county or zone

An area of of resistant aufeis in the main channel of the Sagavanirktok (Sag) River during spring breakup forced the Sag River flow toward Milepost 403 of the Dalton Highway. The high flow from snowmelt and a heavy rain on snow event in the Brooks Range on June 10th exacerbated the impacts to the Dalton Highway.

Where it happened

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The toll

Deaths
0
Injuries
0
Property damage
None recorded
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.

An area of of resistant aufeis in the main channel of the Sagavanirktok (Sag) River during spring breakup forced the Sag River flow toward Milepost 403 of the Dalton Highway. The high flow from snowmelt and a heavy rain on snow event in the Brooks Range on June 10th exacerbated the impacts to the Dalton Highway.

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 Jun 7, 3:44 AM AKST, 4 hours 16 minutes earlier.

Area forecast discussion, Jun 7, 3:44 AM AKST, 4 hours 16 minutes before
Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
444 AM AKDT Wed Jun 7 2023

.SYNOPSIS...
Well above normal temps and dry conditions expected through
Thursday. Conditions will gradually cool to near normal and
moisture will increase on Friday and into the weekend. Isolated
aftn thunderstorms across the Interior Today through Friday.

.DISCUSSION...
Upper Levels and Analysis...
Pattern continues to hold with a quasi-stationary upper low
in the Bering and ridging over the Interior. This will continue
to reinforce the warm air over the Interior with minor instability
for aftn thunderstorms. More moisture begins to advect into the
Interior late Thursday into Friday from the Gulf of Alaska.

Central and Eastern Interior... Very warm condtions across the
Interior continues thru Wednesday, with highs in the mid to upper
70s across most of the lower elevations. The main concern will be
low RHs combined with the warm temps and gusty southerly winds off
the Alaska Range today. Lowest Rh values expected today then
slightly more moist Thursday and Friday. Isolated aftn
thunderstorms across the Interior Today through Friday.

North Slope and Brooks Range...
High pressure over the Arctic Ocean will keep a northeasterly
flow over the North Slope. Some instability will allow for
isolated thunderstorms across the eastern Brooks Range Wednesday.
Otherwise, increasing low stratus and some fog possible along
much of the Arctic Coast Wednesday and cooler temps.

Western Interior and West Coast...
Southeasterly flow around the Bering Sea low will bring increased
moisture and PoPs across the West Coast, while the western
Interior will see a chance for isolated thunderstorms Wednesday
through Friday. High temps in the low 60s near the coast and
lower 70s inland. Cooler on Friday.

Days 4 through 7...
Ridging breaking down over the weekend and cooling to around
normal or slightly below normal temps. There is some signal for
heavy rain across the Brooks Range, but a lot less certainty on
QPF across the Interior. Overall, chance to likely PoPs across the
area thru the period.

Coastal Hazard Potential Days 3 and 4...None.

.FIRE WEATHER...
The main concern will be low RHs combined with the warm temps and
gusty southerly winds in the Alaska Range today. It will be near
red flag conditions mainly in the eastern Alaska Range. RH values
increase slightly Thursday and Friday. Isolated aftn
thunderstorms across the Interior Today through Friday.

Temperatures will gradually decrease and moisture will gradually
increase from Thu through the weekend. There is a chance of
wetting rain Thu night and Fri. Unsettled conditions and generally
cool temps expected thru the weekend.

.HYDROLOGY...
Water is running high on rivers in the lower Yukon Basin, but
will continue to fall slowly. Glacial-fed rivers such as the
Tanana and Kuskokwim will rise this week due to high freezing
levels.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...None.
PK...Small Craft Advisory for PKZ851.
     Small Craft Advisory for PKZ854.
     Brisk Wind Advisory for PKZ857.
&&

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, Central Beaufort Sea Coast

When
June 7, 8:00 AM AKST to June 14, 12:00 PM AKST
Where
Central Beaufort Sea Coast County, 8.13 mi SSW of Deadhorse to 8.3 mi SSW of Deadhorse
Cause
Ice Jam
Reported by
Department of Highways
Coordinates
70.086, -148.553

The main flow of the Sagavanirktok (Sag) River was diverted to the farthest west channel of the river due to aurfeis blocking the channel. The Sag River was pushed up against the Dalton Highway and began to erode the road near Milepost 403.5. On June 7th the road was closed at Milepost 403.5 due to the Sag River eroding the highway to the centerline with the threat of a total washout. This closure shut off the only road access to the oil fields on the North Slope of Alaska. The AK Department of Transportation immediately began hauling rock from a quarry 150 miles away in order to secure the road. The road reopened to one lane traffic on June 8th, although the threat of erosion continued for another week. Runoff from heavy rain and snowmelt in the headwaters of the Sag River reached Milepost 403.5 of the Dalton Highway on June 14th.

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 2023Every state in 2023This day in weather historyWarnings in Alaska, June 2023

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: 1120484.