FORS3237 Lecture 8 Fire Weather PDF

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Summary

Stephen F. Austin State University
FORS3237 Introduction to Fire Management
Professor Dr. Oswald
Term: Spring 2022
Format: in-person...

Description

FORS3237 Introduction to Fire Management Lecture 8 – Fire Weather Continued February 16, 2022 Wind – most variable of weather factors; speeds you see usually posted are how high? Measured with wind gauge; effective wind speed at mid-flame height is important Types of Wind -

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General Winds – in U.S. usually west to east and horizon because of the earth’s rotation Gradient Winds – high to low pressure areas Foehn Winds – gradient wind with topography; topography is an obstacle but influences wind patterns Frontal Winds – associated with mass air movement: cold vs. warm air movement Local Winds – topography driven o Land breeze o Sea breeze o Convection wind o Upslope wind/downslope wind  Diurnal cycle Thunderheads - a rounded, projecting head of a cumulus cloud, which portends a thunderstorm.

Fire Danger Rating -

Wildland fires are episodic, not periodic Conditions of fuels, weather, and ignition source; must occur at the same time Only appears that way to us because we have clocks Higher danger rating = more likely all 3 conditions will be present (fuels, weather, ignition sources)

Burning Period – Daily, often between 10am and 4pm Fire Period – 2 to 10 day “window” of conditions favorable to fires Fire Season – annual occurrence of fires based on long term records -

Florida (winter) Arizona (early summer/late fall) Idaho (late summer early fall)...