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2018 Thanksgiving Day Storm
Category 5 (Extreme) Blizzard(TGMC)
Category 5 "Extreme"(RSI:23.58)
Type(s) Extratropical Cyclone

Nor'Easter-like

Winter Storm

Blizzard

Formed November 21, 2018
Dissipated November 23, 2018
Peak Winds 100 mph
Top Snowfall 41.3" - Boulder, CO
Pressure 952 mbar
Tornadoes 9 Confirmed
Strongest EF3 Tornado
Outages > 23,684
Total damages > $48.96 million

(2018 USD)

Total fatalities > 18
Areas affected Baja, California, Oregon

Idaho, Nevada, Utah,

Colorado, Arizona,

Wyoming, Nebraska,

Kansas

Part of the 2018 North American Winter & 2018 Lucarius Pacific Hurricane Season


Meteorological History

Hurricane Marowak, currently parralelling the coast of Tulavega, which had already suffered blows from Litten and Bastiodon just week earlier was forecasted to become an Extratropical system later the next week. On November 21, Marowak underwent an Extratropical transition as forecasts predicted over Baja California Sur. Almost immediately after, precipitation began to rapidly cool before turning to snow while South of San Diego County. The morning of Thanksgiving, snow had already begun to fall at an astonishing rate, giving Southern California it's first measurable snow since 1967. The system turned due North before accelerating inland over California.

The storm moved passed California before entering Nevada at about 11:30 MDT. The storm intensified to an initial pressure peak of 963 mbar, which is an intensity seen in Category 2 Hurricanes. The cyclone continued to improve structure after a brief weakening period while moving over Utah at 15:00 MDT. Finally, the storm continued it's track West before moving over Colorado at about 18:45 MDT. The storm slowed down extremely to moving at just above 1 mph at about 20:00 MDT before becoming stationary over Boulder County. Finally, the Extratropical Cyclone accelerated after peaking a second time at 952 mbar while moving over Kansas.

Due to influence from a stronger front behind it, the cyclone's center became less and less appearent and it's structure became disheveled to the point it was considered a storm Complex instead of a Cyclone. The morning of November 23, the now very disorganized storm began to embed itself inside the front. At 11:00 MDT, the LMA issued it's final warning on the storm noting that it had no recognizeable center. 2 hours later, the storm was fully embedded in the front.

Impact

This Extratropical Cyclone was a very large and slow system, which allowed the storm to drop up to 40 inches in some places

California

Southern California got up to 6 inches of snow, however it was ruled as beneficial effects due to the wildfires that were occurring during that time period.

In the other places in California, they received record snowfall. The highest in all the state was in Sacramento which was measured at 29.8 inches of snow.

Nevada

Nevada suffered overall minimal damage compared to others that were in the direct path. They only accounted for 10% of confirmed outages and only 2 deaths. The highest snowfall was in Carlin, which measured at 30.3 inches of snow.

Utah

Utah had the most overall damage, with 40% of the total damage from the storm, despite having most of the > 25 inches of snow accumulation centered to a few direct spots. This is owing to the temporary weakening period of higher temps during the early afternoon. Highest snow was in Provo where it is totaled at 39.1 inches

Kansas

Impact to Kansas was kept relatively contained to Western Kansas particularly because the storm was on a deep weakening trend and the fact that by the time it got past Central Kansas, it was very disheveled.

Colorado

Colorado was hit the hardest, with the most all around snow and accounting for 40% of the outage reports. Colorado's highest snowfall was located in Boulder with 41.3 inches, the highest of any location effected by the storm. The strongest tornado spawned by the Cyclone, an EF3 also spent it's life in Colorado's eastern plains near Brighton.

Other Impacts

Arizona

Arizona experienced up to 2 inches of snow in Northern portions and consistent rainfall during Thanksgiving in other parts

Oregon

South Oregon received a persistent mix of rain and snow off and on through Thanksgiving morning. Impact was fairly minimal

Idaho

Idaho had 1 EF0 and 2 of the 4 EF1 tornadoes but received minimal effects besides that

Wyoming

The state of Wyoming received up to 3 inches of snow in Southwest areas but overall no other effects were found

Nebraska

Nebraska was the only state to receive 5 or more inches(Category 1 on the TGMC scale)that was not in the direct path. Other than the 1-5 inches in Southern spots, impact was fairly minimal

Top Snowfall

State Location Snowfall(in)
Colorado Boulder 41.3
Colorado Rifle 40.9
Colorado Aspen 40.3
Colorado Broomfield 39.9
Colorado Idaho Springs 39.2
Utah Provo 39.1
Utah Terra 38.6
Colorado Winter Park 36.0
Utah Strawberry 34.9
Colorado Vail 34.4

Tornadoes

This is a table of all confirmed tornadoes that were confirmed in the storm

Confirmed
Total
Confirmed
F0
Confirmed
F1
Confirmed
F2
Confirmed
F3
Confirmed
F4
Confirmed
F5
9 2 4 2 1 0 0