April 16, 2010 (San Diego) – Effective immediately, the National Weather Service in San Diego is changing its criteria for issuing red flag warnings for fire danger. The change is expected to result in fewer alerts, also saving taxpayers money on overtime staffing for firefighting forces.
The new rule, which applies to all coastal, valley, and mountain zones, removes the criterion for long duration, low relative humidity of less than 10% for 10 hours.
Instead, a relative humidity of 15% with sustained winds greater than 25 miles per hour and/or frequent wind gusts of 35 mph or more for at least six hours will be required to issue a warning, or dry lightning with more than isolated coverage.
For additional information, see: http://www.signonsandiego.com/news/2010/apr/15/officials-hope-policy-shi....