Dense Fog, Grand Valley
- When
- January 9, 3:30 PM MST to January 12, 8:00 PM MST
- Where
- Grand Valley forecast zone
- Reported by
- AWOS,ASOS,MESONET,ETC
- Coordinates
- 39.308, -108.185 (the zone’s center; the record gives no point)
Dense Fog in Colorado, January 9 to 12, 2004
High pressure over the area and snow cover continued to hold a strong inversion over many of the central valleys of western Colorado which resulted in a prolonged period of dense fog. Law enforcement and automated sensors indicated widespread visibilities below 1/4 mile much of the time.
Where it happened
Every event with a place to put it; 2 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
- Tornadoes
- Tropical storms and surge
- Floods
- Wind
- Hail
- Winter weather
- Heat and drought
- Cold
- Fire, smoke and dust
- Marine and coastal
- Other
The toll
- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 2
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 GJT wrote it up.
High pressure over the area and snow cover continued to hold a strong inversion over many of the central valleys of western Colorado which resulted in a prolonged period of dense fog. Law enforcement and automated sensors indicated widespread visibilities below 1/4 mile much of the time. The fog in the Grand Valley was the most persistent. Travel was hampered by the poor visibility. Flight operations at Walker Field Airport were disrupted with numerous flights cancelled or delayed. Freezing temperatures and precipitation of snow grains from the fog resulted in patches of ice and slick spots to form on roadways.
The radar
The national radar mosaic for the moment the first event began.
Event by event
2 dense fog. Local standard time, as filed.
Dense Fog, Upper Gunnison River Valley
- When
- January 9, 4:00 PM MST to January 10, 1:55 PM MST
- Where
- Upper Gunnison River Valley forecast zone
- Reported by
- AWOS,ASOS,MESONET,ETC
- Coordinates
- 38.535, -107.650 (the zone’s center; the record gives no point)
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
- Cold in Pennsylvania, January 9 to 11, 2004
- High Wind in California, January 9, 2004
- Winter Storm in Tennessee, January 9, 2004
- Winter Storm in Virginia, January 9, 2004
- Cold in New Jersey, January 9 to 11, 2004
- High Wind in California, January 9, 2004
- Winter Weather in North Carolina, January 9, 2004
- Winter Weather in North Carolina, January 9, 2004
- Heavy Snow in Kentucky, January 9, 2004
- Winter Storm in North Carolina, January 9, 2004
- Winter Storm in Virginia, January 9, 2004
- Winter Storm in Tennessee, January 9, 2004
More
Every storm in Colorado in 2004Every state in 2004This day in weather historyWarnings in Colorado, January 2004
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 2026-10-01. Each event’s entry at NCEI: 5383218, 5383219.