Why doesn’t the West Coast see major hurricanes?
By CBS Bay Area
Both the Pacific and Atlantic hurricane seasons are in full swing, but when it comes to major landfalling hurricanes, the focus is on the Atlantic, not the Pacific. This week, Zooming with Zoe takes a look at why California doesn’t get impacted by hurricanes like the East Coast.
Historically, the Pacific hurricane season is slightly more active than the Atlantic’s season; 15 vs. 14 named storms, eight vs. seven hurricanes, and four vs. three major hurricanes. One reason for that is the Pacific’s season is slightly longer, running from May 15 – Nov. 30 while Atlantic runs from June 1 to Nov. 30. Another reason is the Pacific is just bigger than the Atlantic, with a lot more room for the storms to grow and develop.
Even though the Pacific normally is more active, one reason the West Coast doesn’t really get hit by them is because of wind direction. Trade winds steer the storms from east to west from the equator to the 30th parallel, meaning the East Coast gets slammed and the West Coast gets spared because the storms usually just go out to sea. If the conditions are right, the storm could get pushed north towards the US, which would then get caught in the westerlies and pushed back to land, but it’s only going to weaken as it gets closer to the West Coast.
A main reason is due to the water temperatures. Hurricanes thrive in warm water, only forming when sea surface temperatures are at least 80°. The East Coast and Gulf see the Gulf Stream, which provides a steady stream of warm water to fuel hurricanes as they move towards land. But the West Coast deals with the chilly California current, moving south along the coast from Alaska towards Mexico and keeping water temperatures from coming close to that 80° mark; normally, it’s in the 60s and 70s.
So, as hurricanes move over cooler water, they fall apart, which is why the West Coast normally only sees the remnants of storms. While on the East Coast, storms strengthen as they move over the Gulf Stream and towards land, which is why they deal with major landfalling hurricanes.
There is only one tropical system on record that produced hurricane-force wind gusts in California; near San Diego back in October of 1858, a category one hurricane brought extensive flooding and wind damage with 75 mph gusts. So, the only time the state has ever felt hurricane-force wind gusts from a hurricane was over 150 years ago. And was before they started the modern naming of hurricanes, so it was just named the San Diego Hurricane.
If an eastern Pacific hurricane should manage to travel far enough west that it crosses the International Dateline before breaking up, it’s renamed as a typhoon, which are what hurricanes are called in Asia.
