National Weather Service United States Department of Commerce

Rare Southern U.S. Winter Storm; Dangerous Cold Weather For Much of the Eastern U.S.; Critical Fire Weather for Southern California

A rare winter storm impacting the Southern U.S. will move offshore Wednesday morning. Behind the storm, arctic air will continue encompassing the eastern two-thirds of the Nation with only a slow return to normal temperatures expected by the end of the week. Moderate to strong Santa Ana winds and low humidity will maintain Critical fire weather conditions in southern California into Thursday. Read More >

Fire Weather Wind Adjustment Tool


UNSHELTERED FUELS: Fuel exposed directly to the wind. No or sparse overstory. Fuel beneath timber that has lost its foliage; fuel beneath timber near clearings or clearcuts; fuel on high ridges where trees offer little shelter from the wind.

1. Fuels usually partially sheltered.
2. Fuels
usually fully sheltered.

Fuel Model

4
California
Chaparal

20' RAWS Wind

Eye Level Wind
(midflame)

13
Heavy Slash
20' RAWS Wind

Eye Level Wind
(midflame)

1, 21, 3
Grass

5, 6, 71
Shrub/Brush

8, 9, 102
Timber litter

11, 12
Light/Medium Slash
20' RAWS Wind

Eye Level Wind
(midflame)


PARTIALLY SHELTERED FUELS: Fuel beneath patchy timber where it is not well sheltered; fuel beneath standing timber at midslope or higher on a mountain with wind blowing directly at the slope.
20' RAWS Wind

Eye Level Wind
(midflame)


FULLY SHELTERED FUELS: Fuel sheltered beneath standing timber on flat or gentle slope or near base of mountain with steep slopes.
Open Stands
20' RAWS Wind

Eye Level Wind
(midflame)

Dense Stands
20' RAWS Wind

Eye Level Wind
(midflame)