Dense Fog in Colorado, December 30, 2002

Name: Dense Fog in Colorado, December 30, 2002
Start: 2002-12-30T05:00
End: 2002-12-30T09:00
Location: Colorado

December 30, 2002 · NWS GJT · 1 event in 1 county or zone

Widespread dense fog developed across the San Juan River Basin. Reports from the Archuleta County sheriff's office indicated visibilities of less than 1/4 mile.

Where it happened

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The toll

Deaths: 0
Injuries: 0
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 GJT wrote it up.

Widespread dense fog developed across the San Juan River Basin. Reports from the Archuleta County sheriff's office indicated visibilities of less than 1/4 mile.

What forecasters said that day

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 Grand Junction, CO wrote its last area forecast discussion before the first event at Dec 30, 4:13 AM MST, 47 minutes earlier.

Area forecast discussion, Dec 30, 4:13 AM MST, 47 minutes before

WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
413 AM MST MON DEC 30 2002

SNOW SHOWERS LINGERING EARLY MAINLY OVER THE CO MTNS THIS MORNING IN
THE WAKE OF AN UPPER TROUGH THAT MOVED ACROSS THE AREA OVERNIGHT.
ENOUGH MOISTURE PRESENT...ESPECIALLY WHERE SOME LIGHT SNOW FELL...TO
PRODUCE AREAS OF LOW CLOUDS AND FOG IN MANY VALLEYS EARLY THIS
MORNING WITH THE LOSS OF MID-LEVEL CLOUD DECK. FOG SHOULD STAY AROUND
PAST SUNRISE. PLAN TO ISSUE DENSE FOG ADVISORY FOR PARTS OF NW CO...
THE WRN END OF THE I-70 CORRIDOR...AND SW CO AS METARS SHOWING 1/4 TO
1/2 MI VIS IN THESE AREAS.

DRIER AND MORE STABLE AIR WILL OVERSPREAD THE FORECAST AREA TODAY...
WITH ONLY A FEW LINGERING MTN SNOW SHOWERS LEFT NEAR THE DIVIDE THIS
AFTN. SHOULD SEE PARTLY CLOUDY IN MANY AREAS THIS AFTN. NW FLOW WILL
SHIFT TO THE WEST BY THIS EVENING...AND THE SOUTHWEST TONIGHT IN
ADVANCE OF THE PAC SHORTWAVE. THIS WAVE LOOKS TO HAVE DECENT JET
DRIVING IT RAPIDLY ACROSS THE GREAT BASIN TUE WITH LESS AMPLITUDE
THAN ITS PREDECESSOR. 700 MB WAA ADVECTION LATER TONIGHT INTO TUE...
WINDY IN THE MTNS ON TUE AS 100KT 300 MB UPPER JET NOSES INTO THE 4-
CORNERS REGION LATE TUE. BEST CHANCE OF SNOW FOR THE NRN/CNTL MTNS
LATE TUE AND TUE NIGHT IN THE COLDER AND MORE UNSTABLE AIR ON THE
NORTH SIDE OF JET...PLUS OROGRAPHICS. MODELS PLACE BEST MOISTURE
ACROSS THE NORTH AS WELL. FLOW SHIFTS TO THE NW FOR WED AS THE
SHORTWAVE TROUGH PASSES...THEN OROGRAPHICS TO KEEP SNOW SHOWERS GOING
MAINLY NRN MTNS ON WED IN THE MOIST NW FLOW.  JAD

EXTENDED...THURSDAY THROUGH SUNDAY...
GFS MODEL SHOWING GOOD CONTINUITY FROM YESTERDAY/S 00Z RUN.  SHORT
WAVE BRUSHES THE NORTHERN ZONES FRIDAY INTO SATURDAY MORNING
TIME FRAME.  AT THIS TIME.. APPEARS BEST ENERGY STAYS NORTH OF
COLORADO SO SNOW CHANCES WILL NOT BE VERY HIGH.  AFTER THIS WAVE..
RIDGE BUILDS ACROSS CALIFORNIA INTO WESTERN COLORADO.. AND THE MAIN
WESTERLIES RETREAT NORTHWARD.  WARMING ALOFT WILL ONLY STRENGTHEN
INVERSIONS KEEPING VALLEYS STAGNANT WITH SOME HAZE AND PERSISTING
STRATUS IN THE UINTA BASIN.  PF

.GJT...DENSE FOG ADVISORY THIS MORNING
       FOR CO ZONES 1..2..6..7..11..22..23 AND UT ZONE 27.

The radar

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

Open the radar archive at this moment

Event by event

1 dense fog. Local standard time, as filed.

Dense Fog, San Juan River Basin

When: December 30, 5:00 AM MST to 9:00 AM MST
Where: San Juan River Basin forecast zone
Reported by: LAW ENFORCEMENT
Coordinates: 37.194, -107.048 (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

Every storm in Colorado in 2002 Every state in 2002 This day in weather history Warnings in Colorado, December 2002

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 2026-09-24. Each event’s entry at NCEI: 5327109.