National Weather Service United States Department of Commerce

Fire Weather Watches/Red Flag Warnings (RFWs) are issued when the combination of dry fuels and weather conditions support extreme fire danger and/or fire behavior. These conditions alert land management agencies to the potential for widespread new ignitions or control problems with existing fires, both of which could pose a threat to life and property.

The issuance of a Red Flag Warning does not predict nor guarantee new fire ignitions.  It warns that predicted fuel and weather conditions are conducive for new ignitions and control problems with existing fires. Additionally, the lack of a Red Flag Warning does not mean that wildfire risk is not present. Very large wildfires can and do occur outside of Red Flag conditions.

A Red Flag event will be triggered for mainly leeward portions of the state when all three of the following criteria are met:

  • Keetch-Byram Drought Index (KBDI) ≥ 500 at specific stations and/or consultation with fire agencies
  • Relative Humidity (RH) ≤ 45 % at specific stations for 2 or more hours
  • Wind ≥ 26 mph at specific stations for 2 or more hours

RFWs will be issued on an island-by-island basis. The following stations will be used for wind, relative humidity, and Keetch-Byram Drought Index diagnosis:

Island Wind RH KBDI
Kauai Port Allen Waimea Heights and/or Mana Waimea Heights and/or Mana
Oahu Bellows and/or Honolulu Airport Honolulu Airport and/or Waianae Valley Honolulu Airport
Molokai Molokai Airport and/or Makapulapai Molokai Airport and/or Makapulapai Makapulapai
Lanai Lanai1 Lanai1 Lanai1
Maui Kahului Airport Kahului Airport and/or Kealia Pond Kealia Pond
Big Island Kealakomo and/or Waikoloa Kohala Ranch, and/or Waikoloa, and/or Kealakomo Kohala Ranch and/or Waikoloa