It seems like whenever there is a particularly windy day in Southern California, non-meteorologists are quick to equate 74 mph wind gusts to hurricane-force winds. The fact is, they aren’t even close. 

What You Need To Know

  • Hurricane-force winds are sustained winds of at least 74 mph

  • Sustained winds and wind gusts are not the same thing

  • Wind gusts are stronger than sustained winds

  • Strong Santa Ana patterns typically aren't even close to hurricane-force strength

What are Hurricane-Force Winds?

Hurricane-force winds are defined based on the sustained wind speed, which is the wind speed averaged over a full minute. Gusts, by comparison, are short bursts of wind, typically lasting only a few seconds. 

The Saffir-Simpson Hurricane Scale defines a Category 1 storm as having sustained winds at or above 74 mph. This is why some media outlets bring up hurricanes when wind gusts are 74 mph, thinking it’s the same as a sustained wind — but it’s not.

Sustained Winds vs. Wind Gusts

Wind gusts are much stronger than their associated sustained winds. The rule of thumb is wind gusts are about 50 percent greater than sustained winds, but it varies with terrain surfaces and the general character of the wind.

The NOAA Hurricane Research division says three to five-second gusts are 30 percent stronger than the sustained wind, which means in order to achieve the equivalent of a 74 mph sustained wind, you need a wind gust to 96.2 mph.

In order for the National Weather Service to issue a high wind warning, sustained winds must be at least 40 mph for an hour, or wind gusts must be at least 58 mph for any given duration. That’s 48 percent higher than the associated sustained wind, closer to the general rule of thumb. By this criteria, in order to achieve the equivalent of a 74 mph sustained wind, you need a wind gust to 111 mph. 

Santa Ana Winds on January 19, 2021

The offshore winds this day were impressive, thanks to an upper-low pressure system enhancing the lower-level winds. 

The only location where winds even came close to hurricane-force was Magic Mountain Truck Trail, a Southern California Edison reporting station at 4500 feet elevation in the San Gabriel Mountains. But you can see directly from the observations that even though wind gusts reached 99 mph, the highest associated sustained wind was 71 mph — short of hurricane-force criteria. 

The Bottom Line

Even though it was windy by Southern California standards, calling Tuesday’s Santa Ana winds hurricane-force strength is simply not correct.