Wyoming, 2015

Dense Fog in Wyoming, April 20, 2015

April 20, 2015 · NWS CYS · 1 event in 1 county or zone

Dense fog formed across the Laramie valley during the early morning hours. The combination of the very low visibility and icy road surface contributed to a deadly multi-vehicle pileup on Interstate 80 about 18 miles west of Laramie.

Where it happened

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The toll

Deaths
2
Injuries
25
Property damage
None recorded
Crop damage
None recorded
Events
1

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 CYS wrote it up.

Dense fog formed across the Laramie valley during the early morning hours. The combination of the very low visibility and icy road surface contributed to a deadly multi-vehicle pileup on Interstate 80 about 18 miles west of Laramie. Multiple injuries and two fatalities were reported.

The radar

The national radar mosaic for the moment the first event began.

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Event by event

1 dense fog. Local standard time, as filed.

Dense Fog, Laramie Valley

When
April 20, 6:00 AM MST to 9:00 AM MST
Where
Laramie Valley forecast zone
Deaths
0 direct, 2 indirect
Injuries
0 direct, 25 indirect
Reported by
Department of Highways
Coordinates
41.655, -105.724 (the zone’s center; the record gives no point)

Very low visibility in dense fog and icy road surface contributed to a deadly, multi-vehicle pileup on Interstate 80 18 miles west of Laramie at mile marker 292 about 8 am. A 22,000 gallon tanker was on fire. Interstate 80 and nearby highways 30 and 287 were closed. WYDOT posted Speeds Advised at 45 MPH and Black Ice Advisory In Effect on their interstate signs. As many as 25 motorists were injured and two were killed in the pileup.

The people who died

As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.

EventDateAgeSexWhereKind
Dense Fog, Laramie Valley2015-04-2058FemaleVehicle/Towed TrailerIndirect
Dense Fog, Laramie Valley2015-04-2023FemaleVehicle/Towed TrailerIndirect

What these are

Dense Fog
Fog reducing visibility to a quarter mile or less, filed where it caused accidents or disruption.

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

The same day elsewhere

More

Every storm in Wyoming in 2015Every state in 2015This day in weather historyWarnings in Wyoming, April 2015

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 2026-09-30. Each event’s entry at NCEI: 571094.