California has many issues: wildfires, mudslides, earthquakes, expensive cost of living, high taxes and lots of traffic. But, one thing it doesn’t have is hurricanes! Why? Aren’t there hurricanes in the Pacific?

There are hurricanes in the Pacific and they are nasty – Eastern Asia takes a pounding from hurricanes — more category 5 hurricanes are found in the Pacific than any other area. Check out this map of past hurricanes and their intensity from NASA:

Hurricanes vs. Typhoons vs. Cyclones

Storms we call Hurricanes are known by a variety of names worldwide. The actual scientific term for these storms is “tropical cyclone” and whether they are called hurricanes, typhoons or cyclones, they are all the same type of storm. From the NOAA: “In the North Atlantic, central North Pacific, and eastern North Pacific, the term hurricane is used. The same type of disturbance in the Northwest Pacific is called a typhoon. Meanwhile, in the South Pacific and Indian Ocean, the generic term tropical cyclone is used, regardless of the strength of the wind associated with the weather system.”

Why Hurricanes Don’t Hit West Coast

Hurricanes are formed when warm water (above 80 degrees) causes the warm, moist ocean air to rise. As the warm air rises, there is less air near the surface and thus new, cooler air rushes in to fill the in where the warm air was, heats up and rises. This over-and-over effect of air warming, rising, and being replaced by new, swirling air creates hurricanes.

Hurricanes don’t hit the U.S. West Coast for two reasons:

First, the water off the West Coast is too cold. Waters off the West Coast rarely rise over 70 degrees. Thus, hurricanes don’t form close to the West Coast and those that approach the west coast lose their energy due to the cool water and air off the coast.

Second, hurricanes form in the tropics generally and move from east to west in the Northern Hemisphere with the trade winds. This brings up an interesting question – if weather moves from west to east in the U.S., why do hurricanes move from east to west? the answer is that there are actually six zones of weather:

The U.S. lies in the “westerlies” area (except for a bit of Florida) and thus our winds generally move west to east.

Hurricanes mainly form in the tropics and those trade winds send the hurricanes moving east to west. As they move north, they tend to straighten and move more northerly and then to the west as the westerlies change its direction. For example, here’s the track that Hurricane Bill took in 2009:

Why are there no Hurricanes that hit South America?

There has only been one recorded hurricane that has hit South America – hitting Brazil in 2004. Why? The answer is technical. Here it is from the NOAA:

The tropospheric (near surface to 200mb) vertical wind shear is much too strong and there is typically no inter-tropical convergence zone (ITCZ) over the ocean. Without an ITCZ to provide synoptic vorticity and convergence (i.e. large scale spin and thunderstorm activity) as well as having strong wind shear, it becomes very difficult to nearly impossible to have genesis of tropical cyclones.