California, 2021

Dense Fog in California, January 11, 2021

January 11, 2021 · NWS HNX · 3 events in 3 counties and zones

With little change in the overall pattern and high pressure remaining dominant over the region, areas of dense fog reformed during the early morning of January 11, but it was more confined to the State Route 99 corridor from Tulare County northward. The fog lifted into a low cloud deck by late morning and dissipated during the early part of the afternoon.

The toll

Deaths
0
Injuries
0
Property damage
None recorded
Crop damage
None recorded
Events
3

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 HNX wrote it up.

With little change in the overall pattern and high pressure remaining dominant over the region, areas of dense fog reformed during the early morning of January 11, but it was more confined to the State Route 99 corridor from Tulare County northward. The fog lifted into a low cloud deck by late morning and dissipated during the early part of the afternoon.

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 Hanford, CA wrote its last area forecast discussion before the first event at Jan 10, 3:32 PM PST, 9 hours 53 minutes earlier.

Area forecast discussion, Jan 10, 3:32 PM PST, 9 hours 53 minutes before
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Event by event

3 dense fog. Local standard time, as filed.

Dense Fog, Merced and Madera

When
January 11, 1:25 AM PST to 11:15 AM PST
Where
Merced and Madera forecast zone
Reported by
ASOS

Merced and Madera reported visibility below a quarter mile.

Dense Fog, Foggy Bottom

When
January 11, 3:15 AM PST to 12:00 PM PST
Where
Foggy Bottom forecast zone
Reported by
ASOS

Hanford reported visibility below a quarter mile.

Dense Fog, Tulare County

When
January 11, 6:45 AM PST to 8:55 AM PST
Where
Tulare County forecast zone
Reported by
AWOS

Visalia reported visibility below a quarter mile.

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 California in 2021Every state in 2021This day in weather historyWarnings in California, January 2021

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: 928492, 928493, 928494.