A low pressure system in the Gulf of Alaska combined with a high pressure system over the mainland to cause a tight gradient through the Chugach Range. This was further enhanced by a cold dome of air located over the Copper River Basin, bringing high winds to Thompson Pass.
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.
A low pressure system in the Gulf of Alaska combined with a high pressure system over the mainland to cause a tight gradient through the Chugach Range. This was further enhanced by a cold dome of air located over the Copper River Basin, bringing high winds to Thompson Pass.
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 Jan 28, 4:18 AM AKST, 10 hours 32 minutes earlier.
Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
418 AM AKST Sun Jan 28 2018
.ANALYSIS AND UPPER LEVELS...
The longwave pattern aloft features two distinct features on water
vapor imagery this morning. The first is a complex upper low
pressure in the southern Gulf. A strong shortwave disturbance on
the eastern edge of the trough is wrapping up a deep surface low
around 974 mb. The other is a high amplitude ridge over the Bering
Sea, stretching well north over the Chukchi Peninsula. Another
feature of interest, one which will play a role in our area, is a
shortwave trough rounding the top of the ridge, diving into
northern Alaska.
At the surface, high pressure dominates the Interior, bringing the
area down to more winter-like temperatures. The gradient between
the high pressure to the north and stronger low pressure in the
southern Gulf/north Pacific puts Southcentral Alaska into an
outflow pattern with stronger winds beginning to develop along the
gaps of the north Gulf coast. High pressure and cloud-less sky
promotes a very cold air mass at the surface with negative 20s to
negative 30s in the Copper River Basin and single digits to
negative single digits elsewhere across southern Alaska.
&&
.MODEL DISCUSSION...
There's not much differences in the models from a synoptic
perspective for the next couple days. Guidance agrees well on the
timing and strength of a shortwave trough dropping in from the
north. Both domains utilized high resolution guidance for the
wind forecast.
&&
.AVIATION...
PANC...Winds will be the active parameter for today's forecast.
The uncertainty revolves around a developing Matanuska Valley
wind, namely how much remains aloft and how much mixes to the
surface. Likely the strongest winds will remain elevated,
resulting in a period of wind shear later this evening with lesser
gustiness at the surface.
&&
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
The upper level ridge centered over the Bering Sea will slowly
retrograde over the next couple of days. Through today and tonight
several vort-maxes will push through Southcentral Alaska, which
will increase the downward mixing of upper level winds. Surface
winds in the Matanuska Valley, the Copper River delta, and the
Thompson Pass/Valdez area will increase sharply today and continue
into Monday morning. These winds will diminish Monday and Monday
night as the northerly winds aloft push westward following the
retrograding ridge. Clear and dry conditions will continue over
the area under the northerly flow. Temperatures will generally be
below normal, especially in areas with little or no wind. The
areas with the higher winds will be a bit warmer.
&&
.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...
Forecast thinking remains largely unchanged for the southwest
mainland through Tuesday as the region remains in dry offshore
flow on the eastern periphery of the stout Bering Sea ridge. Winds
will increase out of the north and become more gusty tonight into
Tuesday as shortwave energy dives down the back of the trough
over the eastern half of the mainland, however temperatures
should remain warm enough to preclude any significant wind chill
concerns in the coming days.
&&
.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...
The strong blocking high will remain as the dominant feature over
the Bering through the middle of the week, with any notable
sensible weather impacts confined to the periphery of the ridge.
Another round of northerly gap winds will impact the Alaska
Peninsula and its coastal waters late tonight into Monday as the
aforementioned shortwaves traverse the region. Out west, the
persistent quasi-stationary frontal boundary will continue to
bring southerly gales and the chance for a few showers to the
western tip of the chain through tonight before finally receding
into the Pacific on Monday.
&&
.LONG TERM FORECAST (Days 3 through 7)...
Starting Tuesday, a high amplitude upper level ridge will be
centered over the Bering while a long-wave trough will be located
over the ALCAN and southeastern Alaska, leading to continued cold
and dry northerly off shore winds. By Wednesday, a shift in the
upper level pattern will begin as a ridge over the Western US
Coast builds back in which will act to tilt the trough/ridge
couplet over Alaska on its side, with the longwave trough moving
over southern Alaska and the gulf, and the longwave ridge moving
over the northern half of the state. There is some disagreement as
to what happens next, with previous model runs showing the trough
moving off to the west which would allow a return to southerly
flow into southcentral by late next week with warmer and wetter
conditions. The EC on the other hand has been consistently much
less aggressive in breaking down what looks to be an area of
strong high pressure with significant cold air associated with it
over the Yukon Territory. This is a scenario that the models are
typically too aggressive to break down ridging over the Mainland,
so as a result the EC is the favored model beyond the middle of
next week as it has consistently been the slowest and further
south with frontal positions, and closest to the current forecast.
This preference keeps ridging cold air/dry air over the South
Mainland with the potential for outflow winds along the Gulf
Coast. The Aleutians and Bering on the other hand would would see
a return to a more warmer, wetter, and more active pattern into
next weekend.
&&
.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Heavy Freezing Spray 127 139 160 165 180 181.
Storm 127.
Gale 121 128 130 131 139 150 155 178.
&&
SYNOPSIS AND MODEL DISCUSSION...MTL
SOUTHCENTRAL ALASKA...BL
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CB
LONG TERM...KVP/DEKSPECIAL WEATHER STATEMENT National Weather Service ANCHORAGE AK 1111 AM AKST Sun Jan 28 2018 AKZ111-131-291115- Matanuska Valley-Northeast Prince William Sound- Including the cities of Palmer, Wasilla, Sutton, Chickaloon, Valdez, and Thompson Pass 1111 AM AKST Sun Jan 28 2018 ...STRONG WINDS EXPECTED FOR THE MATANUSKA VALLEY, THOMPSON PASS AND VALDEZ SUNDAY EVENING THROUGH MONDAY... Strong northerly gap winds will develop across Southcentral late this afternoon through Monday afternoon. The strongest winds can be expected at Thompson Pass, where gusts could reach as high as 70 mph, leading to periods of reduced visibilities from blowing and drifting snow as well as wind chills nearing -40 F. Strong winds can also be expected at Valdez as well as through the Matanuska Valley, including Palmer and Wasilla, where gusts up to 60 mph can be expected.
1 high wind. Local standard time, as filed.
Road Weather Information System station in Thompson Pass (Elev 2740 ft) reported gust of 80 mph starting at 2:50pm 1/28.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Alaska in 2018Every state in 2018This day in weather historyWarnings in Alaska, January 2018
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: 731007.