A prolonged period of well-below-average spring temperatures combined with an above-average winter snowpack created a dynamic breakup of the Yukon River. This resulted in numerous ice jams and snowmelt flooding on the Yukon River.
Every event with a place to put it. Tap one for its entry below.
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.
The episode as NWS AFG wrote it up.
A prolonged period of well-below-average spring temperatures combined with an above-average winter snowpack created a dynamic breakup of the Yukon River. This resulted in numerous ice jams and snowmelt flooding on the Yukon River. Breakup flooding began on May 12th in eastern Alaska in Eagle and ended on June 3rd in the Yukon River delta at the Bering Sea coast. The primary cause of this active flood year was a 1-2 week delay in breakup when compared to typical timing. April temperatures were well below normal, and when temperatures began to warm in early May, it melted the low-elevation snowpack quickly. Because of the relatively quick addition of snowmelt onto strong ice, the ice was more susceptible to jamming and floods. In addition to the late breakup, the snowpack this winter was 1 to 1.5 times greater than the climatological normal for interior and western Alaska. Significant ice jams and associated flooding on the Upper Yukon River resulted in large volumes of ice and water to move down into the Middle Yukon River.
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 May 17, 1:16 AM AKST, 10 hours 44 minutes earlier.
Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
216 AM AKDT Wed May 17 2023
.SYNOPSIS...
The busy weather pattern of the last several days will transition
to a warmer and drier, more summer like pattern with precipitation
diminishing over Northern Alaska as high pressure builds in aloft.
Ice Jam flooding remains a concern along the Yukon River especially
down river of Tanana as the breakup front continues to move down
river. Fire Weather concerns emerge on Thursday, and especially on
Friday with warmer temperatures, low relative humidity values and
winds all expected to flirt with Red Flag Criteria for the Yukon
Flats, as well as the Middle and Upper Tanana Valleys.
&&
.DISCUSSION...
Model Discussion...
The 17th at 00z model suite initialized well against the 00z
surface analysis as well as the 00z upper air observations and
verified well against the 06z surface analysis. Model spread both
between model families and from run to run remains limited in the
short range as well as the mid range. Model spread is reasonable
in the extended range. The models are in good agreement with an
upper level high pressure ridge building north and west out of
the Yukon over Northern Alaska Thursday and Friday and into the
Weekend. This will produce warmer and drier conditions over much
of Northern Alaska into the weekend.
Upper Levels and Analysis...
At 500 mb a deep upper level trough extending south from near the
North Pole to the Bering Strait and then southward into the
Aleutians is anchored by a 534 dam low near the Bering Strait.
This upper level low will weaken rapidly as it replaced by high
pressure building north and east our of Siberia and north and west
from a high pressure ridge over the Yukon on Thursday and Friday.
Upper level high pressure will remain over Northern Alaska into
the weekend as upper level low pressure remains over the Gulf of
Alaska. On the surface a 1014 mb low over Norton Sound this
morning weakens rapidly high pressure builds east out of the
Bering Sea. High pressure will remain over the Bering Sea as low
pressure remains over the Gulf of Alaska Thursday and Friday. Weak
lee side troughing and a thermal trough will develop over the
southern Interior on Thursday and Friday.
Central and Eastern Interior...
The strong chinook winds of the last several days have diminished
with slightly cooler temperatures and drier conditions expected
today. Winds are expected to remain light into the weekend.
Temperatures begin to increase on Thursday and Friday and will
remain warm into the weekend. This will continue snowmelt process
over the higher terrain and will keep river levels running high
into the weekend. Chances of precipitation are minimal into the
weekend. Warm temperatures and dry northeasterly winds will raise
Fire Weather concerns over the Yukon Flats, as well as the Middle
and Upper Tanana Valleys especially on Friday but to a lesser
extent Thursday as well with near Red Flag conditions expected on
both of these days. Both temperature and relative humidity
criteria will be met in these areas on Friday with winds
approaching criteria. Continue to monitor. An easterly wave will
approach the Eastern and Central Interior from the Yukon on Monday
brining a slight chance of thunderstorms over the area.
West Coast and Western Interior...Winter continues its grip over
the Bering Strait where snow and blowing snow continues this
morning with the worst conditions from Saint Lawrence Island to
the Bering coast. Conditions are expected to improve this
afternoon as the system weakens with wind and snow and rain
diminishing. Thursday and Friday brings a transition to a warmer
and drier pattern. Temperatures rise into the 60s again for the
Interior and to near 50 along parts of the coast by Friday.
North Slope and Brooks Range...
Light snow continues to fall mainly over the eastern portions of
the North Slope as a weak low tracks north over the area today.
The focus for snow accumulation will be Prudhoe Bay east. Gusty
east winds as well as snow diminish through the day today as the
weak low exits to the north and east. Expect increasing west to
southwest winds again Thu and Fri with partly clearing skies and
warming temps.
Extended Forecast Days 4-7...
Warm and summer-like weather will grace the Mainland Fri night
through Sun, with some clouds filtering in and some showers
possible Sat afternoon and Sun afternoon near the Alaska Range as
a weak disturbance passes north from the Gulf of AK low. Some form
of ridging looks to maintain itself over the Mainland into mid
week at least, so it looks like some warmer weather should occur
across most areas with no significant storms or fronts in the
near future. An easterly wave moving west out of the Yukon on
Monday will likely produce Isolated thunderstorms over the Eastern
and Central Interior.
Coastal Hazard Potential Days 3 and 4...None.
&&
.FIRE WEATHER...
Winds continue to diminish over the Interior and along and near
the Alaska Range. Light winds are expected today as well as
Thursday and Friday. A warming trend will begins today and will
continue into the weekend with temperatures rising into the mid
60s and lower 70s today over the Eastern and Central Interior.
Temperatures will rise into the upper 60s to mid 70s by Friday.
Minimum relative humidity values will drop into the lower 30s to
mid 20s with the driest conditions expected in the Yukon Flats,
the Middle and Upper Tanana Valley on Friday. Will need to monitor
these areas especially on Friday as Temperature and relative
humidity criteria will likely be met in these areas. Wind
criteria for these areas will be approached on Friday. Hot, Dry
and Windy criteria will likely be threatened to a lesser degree
on Thursday but Friday appearing to be the warmest and driest.
Wind criteria will be close. An easterly wave moving west out of
the Yukon on Monday will likely spark Isolated thunderstorms over
the Eastern and Central Interior.
&&
.HYDROLOGY...
A flood warning has been issued for Buckland along the Buckland
River for ice jam flooding, which was based off the latest spotter
reports from the local area. A flood watch remains in effect for
high water possible from ice jam flooding along the Yukon River at
Tanana. The River Watch Team reports the breakup front moved past
Tanana Tuesday afternoon, with an approximately 120 mile run of
bank-to-bank ice chunks and pans. In place ice sheets downriver
from Tanana are weakening, but there is still the possibility of
an ice jam forming. In addition, water levels will rise to bankfull
levels due to the high volume of ice and water associated with
the ice run moving past the community. If you live near or along
the Yukon River near Tanana stay alert and be prepared to take
action. For additional information see Http://weather.gov/aprfc.
&&
.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Winter Storm Warning for AKZ213.
Flood Watch for AKZ221.
Wind Advisory for AKZ222-225-226.
PK...Small Craft Advisory for PKZ811.
Heavy Freezing Spray Warning for PKZ811.
Brisk Wind Advisory for PKZ814-860-861.
Brisk Wind Advisory for PKZ815-856-857.
Small Craft Advisory for PKZ816-817.
Heavy Freezing Spray Warning for PKZ817.
Small Craft Advisory for PKZ851.
Brisk Wind Advisory for PKZ854.
&&The national radar mosaic for the moment the first event began.
1 flood. Local standard time, as filed.
An ice jam on the Yukon River approx 100 miles downriver from Tanana caused minor flooding in the community.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Alaska in 2023Every state in 2023This day in weather historyWarnings in Alaska, May 2023
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: 1104127.