Subfreezing /below normal temperatures were in place with a snowpack already on the ground across the entire region. A low tracked SE along the outer coast, started off with small snow crystals then rates steadily increased as the system developed.
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 AJK wrote it up.
Subfreezing /below normal temperatures were in place with a snowpack already on the ground across the entire region. A low tracked SE along the outer coast, started off with small snow crystals then rates steadily increased as the system developed. Every community saw some snow from this event and a few saw a short period of sleet. Sea level locations along the southern outer coast warmed enough for rain, but upper elevations and inland locations saw all snow.
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 Dec 20, 4:51 PM AKST, 1 hour 9 minutes earlier.
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
451 PM AKST Mon Dec 20 2021
.SHORT TERM.../ Through Wednesday / The jet becomes amplified on
Tuesday with a NWLY jet streak that crosses the Anchorage area,
then into the northern Gulf of Alaska. Jet streak dynamics will
help to spin up a surface low which then tracks SE with the jet
through Tuesday night. At the mid levels (500mb), the jet streak
is quite strong (110-120+ knots) and moves south a bit faster.
Precip will move in Monday evening, but initially the column isn't
saturated in the dendritic growth zone, aka not many ice crystals
in the clouds. Therefore, a chance of freezing drizzle remains in
the forecast for most of the region at the onset, but only a
light glaze is anticipated. If the freezing drizzle/rain becomes
more prevalent, more parts of the panhandle may be added to the
list of advisories/warnings, but at this point the expected snow
totals are driving those. Yakutat/Haines/Skagway look to get about
3 inches out of this storm, so they have been left out of any
statements for now. As the low progresses SE, snowfall rates pick
up with greatest amounts falling during the Tuesday morning
commute. Petersburg/Wrangell areas ended up with the greatest
snowfall at about 10 inches. Please see the latest
forecast/statement for details in your area.
As the low tracks away to the south through Tuesday night, skies
will clear fairly quickly. Winds will increase out of the north
as well, particularly through the northern Lynn Canal region and
other interior passes. Light to moderate freezing spray becomes
more likely as temperatures drop under clear skies late Tuesday
night. The temperatures over the northern Lynn Canal area are
lowering to lower teens / single digits or colder. Along the road
sub zero temperatures will return.
.LONG TERM...Continued outflow winds and very cold temperatures
are expected to continue through the end of the long-term
forecast period. A relatively weak low looks to move from
northwest to southeast, just skirting past the Panhandle, late
Wednesday night through Thursday morning, which will bring up to
about 30 to 40 percent PoPs and some with minor forecast QPF
values along the Outer Coast. Temperatures will be plenty cold
enough for the precipitation to be all snow, but expect only very
light accumulations if any, due to the very light nature of the
snow. After that moves by, the strong Yukon high will dominate our
weather, once again, with clearing skies and negligible chances
for precipitation due to the steady and strong anticyclonic
offshore flow.
As for the winds, expect the northerly outflow winds to continue
through the period. Small craft to Gale winds are anticipated over
north-south oriented Inner Channels, such as Lynn Canal, and up
to small craft over adjacent Inner Channels. Additionally,
funneling will cause strong gusty winds to blow out of interior
passes perpendicular to the tight pressure gradient, which will be
setup over the Coast Mountains over the northern and eastern
Panhandle. Strong and gusty winds are possible for the Skagway and
Haines areas, as well, with sustained winds of around 25 mph with
gusts in the 40s. Along with the very cold temperatures. Bitterly
cold wind chills are possible. Dress warmly if you must be
outside for a prolonged period of time.
As for the bitterly cold temperatures, 850mb model forecast
temperatures getting down well into the negative 20s Celsius
advecting toward the area will translate into some areas in the
northern and central Panhandle easily dipping below zero for
overnight lows, especially toward the holiday weekend. Areas in
the southern Panhandle look to dip into the single digits for
several nights in a row. Ensemble guidance indicates this
substantial of a temperature drop, as well. MOS does not go quite
as cold as it looks to be 2 to 8 degrees warmer on average for the
overnight lows for the period. MOS does not seem to handle
outflow cold temperature outbreaks as well. Daytime highs do not
look to recover, substantially. Prolonged temperatures this cold
may cause pipes to freeze.
Forecast confidence is about average. There is a little
uncertainty over the exact track of the low that will skirt by the
Panhandle late Wednesday night into Thursday. This morning, the
spread was pretty even. Therefore, an even blend of the
GFS/ECMWF/Canadian/NAM was used to get an average track for the
low center.
&&
.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Storm Warning from 7 PM this evening to 7 PM AKST Tuesday
for AKZ026.
Winter Weather Advisory from 9 PM this evening to 9 PM AKST
Tuesday for AKZ027-029.
Winter Weather Advisory from 7 PM this evening to 4 PM AKST
Tuesday for AKZ024.
Winter Storm Warning from 6 PM this evening to noon AKST Tuesday
for AKZ025.
Winter Weather Advisory from 6 PM this evening to noon AKST
Tuesday for AKZ020>022.
Winter Storm Warning from 9 PM this evening to 9 PM AKST Tuesday
for AKZ028.
Strong Wind Tuesday afternoon for AKZ018.
MARINE...Gale Warning for PKZ012-013-022-042-043-051-052-310.
Small Craft Advisory for PKZ011-021-031>034-036-041-053.
&&
Bezenek/JLC
Visit us at http://www.weather.gov/Juneau7 heavy snow. Local standard time, as filed.
A trained spotter in Juneau reported 6.5 inches of new snowfall. Storm total for the entire storm was 11 inches.
Alaska Department of Transportation reports multiple trees down due to heavy snow. 6 inches of heavy snow fell from this storm in addition to the snow load already on the trees.
Harbormaster at Tenakee Springs reports 6 to 8 inches of snow overnight.
A trained spotter reported 8.8 inches of snow just south of Petersburg along the Mitkof Highway.
A trained spotter in Haines reported 7 inches of snow.
A trained spotter in Wrangell reported 7.5 inches of snow from this event in 13 hours.
County official estimates 5 to 6 inches of snow before 1 pm of snow in Thorne Bay. Tree fell on power line due to accumulated snow load.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Alaska in 2021Every state in 2021This day in weather historyWarnings in Alaska, December 2021
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: 1000305, 1000310, 1000313, 1000308, 1000306, 1000307, 1000317.