Lifeguards
and locals around the Encinitas area spotted multiple
waterspouts beyond the kelp beds just after 12 p.m. Up
to seven waterspouts appeared all at once, some lasting
as long as 20 minutes.
Our very
own Pat Powers took
pictures of the waterspouts, Please click below
Waterspouts off the San Diego County coast are
fairly common, and the vast majority have been
benign. Some, however, have been quite destructive.
A waterspout is a weak vortex, or spinning column of
air, over water. It is usually not associated with
the large-scale storm rotation found with tornadoes.
Jim Purpura, the meteorologist in charge at the
National Weather Service's Rancho Bernardo office,
said 12 to 20 waterspouts occur off the San Diego
County coast in the average year.
"They are
generally not a great danger, but small boats have
been flipped around,” Purpura said. “Most don't move
ashore. They're considered tornadoes if they do move
ashore.”
In a true waterspout, Purpura said, the rotation
begins underneath the cloud base. But some vortexes
that are called waterspouts are actually tornadoes
over water, he said. In those cases, the rotation
begins in the mid-levels of the storm.
Waterspouts seen offshore often form when Pacific
storms with very cold air aloft pass over
comparatively warm waters. The air directly above
that warm water wants to rise, while the cold air
above wants to sink.
The islands off the Southern California coast often
add another necessary element for waterspout
development. When cold, moist air masses moving east
or southeast hit the islands, the air masses split,
then converge on the other side. This “island
convergence” can contribute to the rotation needed
for the formation of a waterspout or tornado.
One waterspout that moved ashore in Chula Vista in
April 1956 caused damage to 60 homes and a school.
Two people were injured by flying glass. In October
1961, at least 10 waterspouts were seen between
Oceanside and Del Mar. One of the spouts came ashore
in Carlsbad, and three people were injured by flying
debris.
Another waterspout that moved over land caused the
most injuries associated with a tornado in county
history. In April 1926, eight people were hurt and
roofs were ripped off homes in National City.
Steve Vanderburg, a forecaster for the National
Weather Service, said more twister-caused injuries –
and perhaps even fatalities – are inevitable in the
county because urban sprawl has increased the odds
of a strike.
