Offshore winds, or Santa Ana winds, are winds that blow from the land to the ocean. They originate in the Great Basin and have a variety of effects on California and its residents.
To one person, they are a burden and to another they are a blessing. Therefore, SoCal has a love-hate relationship with Santa Ana winds.
When most people think of Santa Ana winds, they think of hot dry winds that fuel wildfires, wildfires that destroy everything in their paths. This is true, especially in late summer and fall when temperatures in SoCal can easily reach the century mark even without the help of Santa Ana winds.
When you add the compressional warming, temperatures can soar to near 120 degrees. As the winds descend mountain tops, they heat and speed up, making wildfires indefensible.
Santa Ana winds have a milder effect on SoCal after the hot dry season. During winter months when the grasses and trees flourish by rains from winter storms, Santa Ana winds can bring mild to warm temperatures during the cold season... well, cold by SoCal standards.
So we can get beach weather in the middle of winter. When Santa Ana winds blow in winter, the air mass originates at near-freezing temperatures, so they don’t heat up as much as in summer or fall.
When they undergo compressional warming, they warm into the 70s and 80s. This makes for perfect beach weather in the winter months. The image below captures people enjoying the beach on Christmas Day last year when Santa Ana winds led to temperatures near 80 degrees.
Not only this, the Santa Ana winds balance out the sea breeze and we get windless afternoons near the coast. Windless afternoons at the beach are a hot commodity, as the sea breeze is the standard and is hard to overcome.
Surfers also love Santa Ana, or offshore, winds. Not only do they bring warm weather to the beaches during the cool months, they also help with the waves. When winds blow from the ocean to the land, they have a tendency to “blowout” the surf.
Onshore winds lead to choppy waters and bumpy waves. Also, onshore winds blow over the top of breaking waves, which lead to waves “walling” over. Instead of waves having a ridable face, waves that “wall out” break all at once and have no shape.
During Santa Ana wind events, the winds blow from land to ocean. During offshore wind events, the water remains smooth and glassy. Waves hold their shape and have a ridable face. Often the offshore winds “hold up” the face of the wave until the last moment, and then they break with a hollow face.
It is the hollow face, or tube, that surfers love to ride. Notice the offshore spray in the image below.
Santa Ana winds can have negative effects on those who suffer from allergies. When winds blow from the desert to the ocean, they pick up allergens that can wreak havoc on the sinuses.
Santa Ana winds pick up desert dust and pollens and bring those allergens to the coastal valleys and basins. Under prevailing conditions, winds blow from the ocean to the land. This ocean air is clean and free of allergens.
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