Three back-to-back snowstorms impacted Southcentral and, to a lesser degree, Southwest Alaska over the course of an 11-day window in early December. These snowfall events resulted in particularly significant impacts to the Matanuska-Susitna Borough and Anchorage Borough areas.
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 AFC wrote it up.
Three back-to-back snowstorms impacted Southcentral and, to a lesser degree, Southwest Alaska over the course of an 11-day window in early December. These snowfall events resulted in particularly significant impacts to the Matanuska-Susitna Borough and Anchorage Borough areas. These conditions occurred as a highly amplified and transitory pattern affected Southern Alaska, bringing 3 to 5 feet of snow to the Matanuska-Susitna and Anchorage Boroughs within the December 5 to 15, 2022 window.
There were a number of commonalities between the three snow events as follows:
1. All snowstorms occurred as a result of frontogenetically induced lift and associated banded snow.
2. All snowstorms occurred in conjunction with a mature trough, indicating increased instability associated with the pattern.
3. All snowstorms were reinforced by some version of an atmospheric river feeding the system.
4. All snowstorms were associated with a weak surface low. More frequently during the winter months, strong lows and associated wind fields produce upslope/downslope effects which tend to limit widespread heavy precipitation to the Gulf coast areas. In this case, winds crossing the mountains were generally weak, which allowed for a particularly long period of snow west of the Kenai and Chugach Mountains.
It is uncommon to see three storms in a row with such similar characteristics.
In all cases, these ingredients came together to produce abundant snowfall, with the heaviest snowfall generally falling across the higher elevations. The three events occurred December 6-7, 2022, December 11-12, 2022, and December 14-15, 2022, resulting in 3 to 5 feet of snow total over the course 11-day period. Periods of light snowfall in between these dates were noted, but did not have a meaningful impact on snow totals.
These snowfall events hit a few records. For instance, in the city of Anchorage, they hit the 14th highest snowfall amount for a 2-day period December 11-12, 2022 with 16.2 inches of snow. More notably, the only other 11-day period to see higher amounts on record was in 1996 with 44.6 inches, while this 11-day period measured 41.1 inches of snow. To put this event in perspective, these systems pushed Anchorage to the third snowiest snow-year to date and within six tenths of an inch of the snowiest December on record as of December 16, 2022.
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 Anchorage, AK wrote its last area forecast discussion before the first event at Dec 11, 5:39 AM AKST, 9 hours 10 minutes earlier.
Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 539 AM AKST Sun Dec 11 2022 .ANALYSIS AND UPPER LEVELS... The pattern remains highly amplified across the Gulf Of Alaska and North Pacific. On satellite imagery (CIMSS MIMIC PW) there is a fetch of modified tropical moisture that is 300 miles wide and extends over 2,000 miles south into the Central Pacific which is impressive. This deep fetch of moisture is entrained into the new low that will be entering the Gulf Of Alaska today. The jet is north of the Alaska Range with a jet core of 150 knots. Early this morning the radars at Kenai and King Salmon have been active. Additionally on satellite imagery there is the remnants of an occluded front over the eastern Bering and a new low near Attu Island. && .MODEL DISCUSSION... The models are in decent synoptic agreement. By 12z Monday there are some subtle difference in the low track for the Gulf and the next Bering low. The biggest forecast challenge continues to be dialing in the precipitation and snowfall accumulations across Southcentral. In the coastal areas, precipitation type also remains a challenge. && .AVIATION... PANC...Overnight the cigs dropped below 010 at PANC. On satellite imagery (Nighttime Microphysics) the Anchorage Bowl and Cook Inlet are just covered. With the low moving into the Gulf, cigs will bounce all over the place. Light winds persist for this TAF package. && .SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Sunday through Tuesday). The plume of moisture riding along the jet stream form the Pacific is moving over Southcentral Alaska today and will provide the snow for the myriad of winter storms warnings that cover the area. The beginning of the snow has already made it up Cook Inlet to Anchorage early this morning. However, the way the low near Kodiak tracks will bring cross-barrier easterly and southeasterly winds over the Kenai and Chugach Mountains today. This brings us right to the biggest forecast question: How will this cross- barrier flow impact snow amounts today for the Kenai Peninsula northward through the Susitna Valley? Typically, there is downsloping that will keep snow from occurring on the lee side of the mountains. However, when the moisture is this deep, it can often overwhelm the downsloping, though that is a more typical late summer and Fall situation when that happens. In short, the snowfall for the interior Kenai Peninsula as well as Anchorage and Palmer will likely not be very much most of the day today due to this cross-barrier flow. When it weakens this evening, the snow intensity will rapidly increase and that is when the big snow accumulations will occur from this system for these areas: This evening though early Monday morning. It looks at this point like the snow may end sooner on Monday morning for these areas as well and not persist well into the afternoon due to the 500 mb trough moving east of these areas by noon Monday. The western Kenai Peninsula near Cook Inlet is a bit of a different story for today. While the cross-barrier flow/downsloping will occur closer to the mountains, areas near the Inlet will be back to the upward vertical motion and snow is expected to be heavy at times today into tonight for Nikiski, Kenai Soldotna, and along the Sterling Highway southward toward Ninilchik. In addition, the gusty northerly winds will bring in periods of blowing snow which will also reduce visibility today through this evening. Blowing snow is also expected through Turnagain Pass and Turnagain Arm today into tonight where visibilities may get down to one half mile in the snow and blowing snow. Occasional lower visibilities are also possible. Periods of heavy snow from late this afternoon into Monday night is also expected in the Copper River Basin where there is also a winter storm warning in effect due to the snowfall. Thompson Pass is at risk for significantly reduced visibilities in blowing snow from late tonight through Monday night. The earlier ending time for the snow over much of the area due to the quicker passage of the 500 mb trough is probably the biggest change in the forecast from yesterday. && .SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3: Today through Tuesday night)... Snowfall arrived on schedule overnight as a low rooted within a deep tropical moisture tap developed south of the Alaska Peninsula (AKPen). An associated shield of light to moderate snowfall will continue to pivot across Bristol Bay and the Lower Kuskokwim Valley north of this low as it heads past Kodiak Island and into the Gulf today, resulting in a broad swath of additional snowfall of around 4 to 9 inches across this axis through tonight. Winter Weather Advisories remain in effect for both Bristol Bay and the Lower Kuskokwim Valley as the prolonged snowfall event continues across both of these regions. By tonight, snow will end from west to east as a push of much colder, drier air begins to work in from the northwest. Winds will become northwesterly and gustier as the low exits, perhaps resulting in some minor blowing and drifting of the fresh snowfall after falling snow shuts off. Most of Monday should stay fairly clear and cold as a shortwave ridge brushes past ahead of the next system of interest materializing over the Bering Sea. By Monday evening, a front associated with another Bering low will approach the coastline, resulting in rapidly increasing southeast winds as another batch of snowfall moves inland from southwest to northeast. This front does not appear likely to drive a particularly warm air mass back in as it encroaches on Southwest, but some mixing with or changeover to rain will again be possible near the immediate coastline across Bristol Bay. Blowing snow will likely be an issue Monday night along the Kuskokwim Delta Coast as the front initially approaches as falling snow and combines with southeast winds gusting up to 45 mph. Significant blowing snow is unlikely to last for an extended period, however, with the front weakening and stronger winds diminishing across the Kuskokwim Delta by early Tuesday morning as the parent low pushes onshore. Farther south, strong westerly and onshore winds will push into Bristol Bay early Tuesday, potentially resulting in abnormally high water levels across portions of the Bristol Bay coastline until winds subside later in the day. Light snowfall will meanwhile spread across more interior portions of Southwest on Tuesday, with snowfall then ending area-wide from west to east Tuesday night as the low exits into the central Interior. && .SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3: Today through Tuesday night)... Relatively calm conditions exist across the Aleutian Chain and Pribilofs for the moment, with most of the southern mainland feeling the effects of the more active pattern. Cold northwesterly flow around a shortwave ridge advancing across the Bering will help drive up gusty gap winds along and south of the eastern Aleutians and Alaska Peninsula by this afternoon into tonight, with 40 to 50 mph gusts possible out of bays and passes on the Pacific side. To the west, the next noteworthy system will cross the western Aleutians into the Bering by tonight, sending winds up to gale force and light to moderate rain across as its occluding front progresses along the Aleutian Chain. A brief period of snow will be possible as the front approaches the Pribilofs early Monday morning before low level temperatures warm and change falling precipitation with the passing front to rain. As the low and attendant front approach Southwest late Monday into Tuesday morning, a core of gale force winds with gusts to storm force will develop on the south of the center, advancing along and north of the eastern Aleutians into the Alaska Peninsula through Tuesday. Another relative break in the pattern is likely by Tuesday night as the low weakens and moves northeast into the southern mainland. && .LONG TERM FORECAST (Days 4 through 7: Wednesday through Saturday)... Very active weather looks to continue throughout southern Alaska and Bering Sea in the long term. The main features of concern are a high amplitude trough over the Bering and north Pacific and a Rex Block from British Columbia south to the West Coast. The main uncertainty in the forecast is related to the interaction of the storm developing over the north Pacific on the southern edge of the trough axis and the blocking ridge as it moves east. With the high amplitude trough/ridge pattern, ample warm air and an atmospheric river are expected to move north into the southern Mainland. Right now deterministic guidance has two main storm tracks, one through the eastern Bering and into the Interior and the other into Bristol Bay and the Gulf of Alaska. The east/west position of the low will determine precipitation type midweek for both Southcentral and Southwest. The ECMWF and Canadian solutions show a more amplified solution with a low farther to the west (eastern Bering and Interior Track), which would lead to rain across the southern Mainland Wednesday and Thursday, with chances for snow on the backside as the system occludes. The GFS solution has a more easterly storm track, which would lead to heavy snow over the Kuskokwim River areas, rain for Bristol Bay, and mixed precipitation for Southcentral. The forecast is highly uncertain and pertains in many ways to the north/south positioning of a low moving across the southern Mainland on Tuesday, with the more southern solution helping to keep temperatures aloft cooler and visa versa. This storm will likely be very impactful, but the question of how it will be impactful (rain vs snow) is to be determined. && .AFC WATCHES/WARNINGS/ADVISORIES... PUBLIC...WSW 101 111 141 145 121 125 152 161. MARINE...Storm 119 130 132. Gale 150 155 160 165 170 172 173 174 175 176 177 178 179 180 412 413 414 120 121 125 131 138 139. && SYNOPSIS AND MODEL DISCUSSION...PJS SOUTHCENTRAL ALASKA...EZ SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...AS LONG TERM...CJ
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
209 PM AKST SUN DEC 11 2022
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0706 AM SNOW TALKEETNA, AK 62.23N 150.07W
12/11/2022 M0.5 INCH MATANUSKA-SUSITNA AK PUBLIC
&&
EDPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
210 PM AKST SUN DEC 11 2022
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0956 AM SNOW TALKEETNA, AK 62.23N 150.07W
12/11/2022 M1.1 INCH MATANUSKA-SUSITNA AK PUBLIC
&&
EDPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
211 PM AKST SUN DEC 11 2022
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0942 AM DENSE FOG KODIAK CITY, AK 57.81N 152.38W
12/11/2022 KODIAK ISLAND AK PUBLIC
CORRECTS PREVIOUS DENSE FOG REPORT FROM 1 NE
KODIAK.
&&
EDPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
214 PM AKST SUN DEC 11 2022
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1005 AM DENSE FOG KODIAK CITY, AK 57.80N 152.38W
12/11/2022 KODIAK ISLAND AK PUBLIC
SPOTTER ESTIMATED DENSE FOG LESS THAN 1/4
MILE.
&&
EDPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
215 PM AKST SUN DEC 11 2022
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1011 AM SNOW NIKOLAEVSK, AK 59.77N 151.60W
12/11/2022 M4.2 INCH KENAI PENINSULA AK PUBLIC
&&
EDPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
216 PM AKST SUN DEC 11 2022
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1105 AM SNOW NIKISKI, AK 60.71N 151.37W
12/11/2022 M11.5 INCH KENAI PENINSULA AK PUBLIC
&&
ED4 heavy snow, 3 winter weather, 1 winter storm. Local standard time, as filed.
Chefornak and Toksook webcams showed visibilities of about a 1/2 mile; Kipnuk observations showed 1/2 mile or less from 00:32z-0124Z.
The Cape Newenham observation showed visibilities of 1/2 mile or less from 2336z-0316z; the Platinum observation showed visibilities of 1/2 mile or less several times between 0045z-0242z.
Illiamna SNOTEL measured a snow depth difference of about 8 inches.
A third round of heavy snow occurred December 14 through 15 resulting in about a foot of snow across the Anchorage Borough. This snowfall was produced as a tropical moisture plume spread northward and combined with an upper-level disturbance transitioning across the state. The bulk of the snowfall arrived late Wednesday afternoon and continued through Thursday morning. Unlike the last two snow events, snow fell in a more uniform manner. Snowfall reports received ranged from 7.5 inches to 12 inches within a 12 hour period, on top of the snowfall still on the ground from the previous two December snowfall events, leading to increased impacts across the Borough. A member of the public reported 11.7 inches in Eagle River and another reported 12 inches on Northern Lights Blvd within a 12 hour period.
A third round of heavy snow occurred December 14 through 15 resulting in about a foot of snow across the Matanuska Valley, on top of the snowfall still on the ground from the previous two December snowfall events, leading to increased impacts across the Valley. This snowfall was produced as a tropical moisture plume spread northward and combined with an upper-level disturbance transitioning across the state. The bulk of the snowfall arrived late Wednesday afternoon and continued through Thursday morning. Unlike the last two snow events, snow fell in a more uniform manner. The verifying observation came in from Big Lake where 16 inches of new snow were measured over a 12 hour period.
A third wave of heavy snow hit southcentral Alaska within an 11-day period in early December. This snowfall was produced as a tropical moisture plume spread northward and combined with an upper-level disturbance transitioning across the state. The bulk of the snowfall arrived late Wednesday afternoon and continued through Thursday morning. Unlike the last two snow events, snow fell in a more uniform manner. DOT foremen reported 28 inches of new snowfall between December 14th and 15th. The Valdez SNOTEL reported about 18 inches of snow depth difference over the same period.
A third wave of heavy snow hit southcentral Alaska within an 11-day period in early December. This snowfall was produced as a tropical moisture plume spread northward and combined with an upper-level disturbance transitioning across the state. The bulk of the snowfall arrived late Wednesday afternoon and continued through Thursday morning. Unlike the last two snow events, snow fell in a more uniform manner. A member of the public measured 24 inches of new snow in a 24 hour period in Slana near the Tok Cutoff. Other observations ranged from 6 to 9 inches along the road system.
A third round of heavy snow occurred December 14 through 15 resulting in about a foot of snow across the southern portion of the Susitna Valley. This snowfall was produced as a tropical moisture plume spread northward and combined with an upper-level disturbance transitioning across the state. The bulk of the snowfall arrived late Wednesday afternoon and continued through Thursday morning. Unlike the last two snow events, snow fell in a more uniform manner. Taunnie Boothby, the Matanuska-Susitna Borough Floodplain Manager, reported a total of 14 inches of new snow in a 24 hour period, 14 miles up the Willow-Fishhook Road.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Alaska in 2022Every state in 2022This day in weather historyWarnings in Alaska, December 2022
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: 1098716, 1098717, 1098718, 1098721, 1098722, 1098724, 1098726, 1098727.