California will soon rank heat waves like hurricanes

Heat waves in California will soon be ranked by severity in a manner similar to hurricanes and other extreme weather events.

On Friday, after one of the worst heat waves in recent memory, Gov. Gavin Newsom signed a bill authored by Assemblymember Luz Rivas that would require the state to devise "a statewide extreme heat ranking system" no later than Jan. 1, 2025. The bill's text says the system — which would be the first in the nation for heat waves — should be modeled after "red flag" warnings for wildfire risk, as well as the National Oceanic and Atmospheric Administration's naming and ranking system for hurricanes and tropical storms.

"Ranking heat waves will be a powerful new tool to protect all Californians alongside Gov. Gavin Newsom's Extreme Heat Action Plan," Insurance Commissioner Ricardo Lara said in a statement. "I applaud the governor's and the bill's joint authors' continued leadership on these necessary extreme heat investments and policies that will save lives and close the protection gap for our most at-risk communities as we face more heat waves in the years ahead."

The system could use any number of ranking conventions. During the first year of the COVID-19 pandemic, California used a color-coded tier system to rank counties by their level of community viral transmission, and the state already uses the National Weather Service's conventions for wildfire risk. NOAA's hurricane ranking scale classifies the weakest hurricanes as Category 1 and the strongest as Category 5.

The ranking system bill was one of four pieces of legislation Newsom signed Friday that are related to heat waves. A separate bill creates an advisory committee to study the effect of heat waves on the state's economy, while another directs the state Department of Public Health to research the impacts heat has on pregnant workers. The final heat-related bill Newsom signed gives cities and counties more power to finance climate change adaptation programs.