Alaska, 2021

Heavy Snow in Alaska, November 12, 2021

November 12, 2021 · NWS AJK · 2 events in 1 county or zone

A low pressure system brought warning level snow amounts to the Haines Highway in the northern Alaska Panhandle.

The toll

Deaths
0
Injuries
0
Property damage
None recorded
Crop damage
None recorded
Events
2

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 AJK wrote it up.

A low pressure system brought warning level snow amounts to the Haines Highway in the northern Alaska Panhandle.

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 Juneau, AK wrote its last area forecast discussion before the first event at Nov 12, 6:36 AM AKST, 24 minutes earlier.

Area forecast discussion, Nov 12, 6:36 AM AKST, 24 minutes before
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
636 AM AKST Fri Nov 12 2021

.SHORT TERM.../Through Saturday night/...A warm low level airmass
moved in overnight and completely overwhelmed cold air at the
surface in all locations except for Haines and the Haines Highway.
Consequently, precipitation overnight came as rain everywhere
except Haines. The winter weather advisories for Skagway and
Juneau were cancelled with the morning forecast issuance. The
advisory for Haines remains and that is the only location that
snowed reliably through the night. Temperatures warmed through the
night in most other locations and this is well depicted in 850 mb
charts. With little to no chance for solar insolation today, some
locations may have already seen their max temperature for the day
with highs ranging from the mid 30s over the north to the upper
40s to the south.

The associated low remains on track for a landfall in the
vicinity of Cross Sound, but is showing clear signs of a
weakening trend in both satellite imagery and in observed wind
speeds. As a result, the wind forecast for northern Lynn Canal was
adjusted down significantly for this morning. An abrupt shift in
wind direction over the northern half of the Panhandle is still
expected as the low skips inland and moves northeast into the
Yukon. The potential for high end small craft southerlies over
Lynn Canal as this happens, so the wind forecast for this evening
was not modified.

As the low and associated warm low level air moves off into
Canada, colder air will advect in from the west and produce a
cooling trend for the remainder of this short range forecast
period. Concurrently, PoP will decrease, so accumulating snow at
lower elevations is becoming less and less likely through the
weekend.

.LONG TERM.../ Sunday through Friday as of 10 PM Thursday /
Diminishing precipitation will give way to clearing skies through
Sunday afternoon, at least across the N half of the panhandle. The
cause of the clearing skies will be an outflow event which will
take place as the pressure gradient strengthens between a new low
moving N out of the southern Gulf and a high in the Yukon. Expect
that with this outflow event, it is likely that breezy conditions
will be seen across at least the N half of the panhandle. Lynn
Canal will likely see gale force winds, and have added small
craft winds in through many of the central inner channels. There
may also be an opportunity for a weak to moderate strength
mountain wave event to setup over downtown Juneau, though am not
yet confident in this given the differences in timing of the low
to the south.

The windy conditions will most likely begin to subside Monday
afternoon through Monday night as the low in the south attempts to
advance into the panhandle, before being deflected back to the S
as its associated trough moves out of the area. It still looks
like the southern panhandle will experience the bulk of any
significant precipitation with this system. The far N panhandle
will likely stay fairly dry, with precip chances slowly increasing
through the Icy Strait Corridor on South.

Disagreement among ensembles and operational runs alike rapidly
increases after this time period, but it does look like the low
in the S departs the area by Tuesday. There are increasing
indications that a new wave could impact the area Tuesday or
Wednesday, but forecast uncertainty means this is not yet set in
stone. Looking even further afield, there are hints that
significant cooldown for late next week could be in the works-
something which would likely be joined with a substantial outflow
event. However, confidence in this event remains low at this time.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Strong Wind until 6 PM AKST this evening for AKZ027.
     Winter Weather Advisory until noon AKST today for AKZ019.
     Winter Weather Advisory from 6 AM to 3 PM AKST Saturday for
     AKZ017.
MARINE...Gale Warning for PKZ041>043-310.
     Small Craft Advisory for PKZ011>013-021-022-031>034-036-051>053.

&&

Fritsch/GFS

Visit us at http://www.weather.gov/Juneau

Event by event

2 heavy snow. Local standard time, as filed.

Heavy Snow, Haines Borough and Lynn Canal

When
November 12, 7:00 AM AKST to 6:00 PM AKST
Where
Haines Borough and Lynn Canal forecast zone
Reported by
Law Enforcement

United States Customs and Border Patrol reported 10 inches of snow at 7 am along the Haines Highway. A total of 16 inches of snow fell by 6 pm that evening.

Heavy Snow, Haines Borough and Lynn Canal

When
November 12, 10:00 AM AKST to 6:00 PM AKST
Where
Haines Borough and Lynn Canal forecast zone
Reported by
Trained Spotter

A trained spotter in Haines reported 6 inches of snowfall, with the majority of it falling from mid-day to mid-afternoon.

What these are

Heavy Snow
Snowfall reaching the local warning threshold without the other hazards of a winter storm.

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

The same day elsewhere

More

Every storm in Alaska in 2021Every state in 2021This day in weather historyWarnings in Alaska, November 2021

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: 994849, 994850.