Santa Ana, Diablo Winds and the 1991 Oakland Firestorms Anniversary

Last month's wildfires in Texas, spurred by drought and winds from Tropical Storm Lee, call the mind the anniversary of another big fire . 20 years ago, in California , firestorms broke out in Oakland and Berkeley Hills, touched off by "Diablo winds." Here is a Q-and-A about those winds and the devastation wrought by fire in that event, along wit h links for resources.

What is a "Diablo wind?"

"Diablo" is a Spanish word meaning "devil." Diablo winds were so-named for the wild destruction they caused in parts of California in 1991 and 1992. Diablo winds most typically occur over the San Francisco Bay area. Like the more familiar Santa Ana winds, Diablo winds are hot, dry northeasterly offshore 40-mph gusts noted for producing wildfires in southern California and the Baja Peninsula. Santa Ana winds occur most frequently in late fall and early winter and form over the Great Basin. They kick up over high desert elevations, while Diablo winds form in the mountains around the Bay.

What is a drainage wind?

Both Diablo and Santa Ana winds are drainage winds. A drainage wind is also called mountain or Katabatic wind. The term comes from the Greek for "moving downhill." In a Katabatic, or fall wind, gravity sucks high density air down slopes, at speeds that can reach hurricane force. Notable drainage winds include France's Mistral, the Bora of the Adriatic Sea, New Zealand's "Barber" and the Oroshi wind of Japan.

What is a firestorm?

As wildfire spread by forward directional movement, a firestorm, driven by gusting cyclonic winds, is more erratic. It flings embers around, causing fires break out. Firestorms create their own winds which propel the blaze in crazy patterns.

What happened in the 1991 Oakland Firestorm?

On Oct. 19, during the windy season, an improperly maintained brush fire set five acres alight in Berkeley Hills, Calif. Diablo winds with gusts up to 65 mph, caused the blaze to restart and develop into a firestorm. For three days, the fire ravaged a 1,520-acre area.

What was the death and damage toll?

The firestorm, called also the East Bay Hills Firestorm and Tunnel Firestorm (as it broke out near the Caldecott Tunnel), is notorious not for the area of land it covered, but the the damage it caused. Firestorms caused $1.5 billion in damage, burning 3,354 homes and destroying 437 apartment complexes and condominiums. 25 lives were lost in this terrifying and unexpected storm.

How has firefighting changed in response to the 1991 firestorm?

Building construction changed to create safer, fire-resistant structures. Updates were made to firefighting equipment and public address systems. When a brush fire struck in 2008, in the same location, lesson learned from the 1991 firestorm, enabled firefighters to contain the blaze in 90 minutes. The community will also host a twentieth-anniversary memorial tribute.

To help children understand firestorms, visit these links for details:

Tikvah Means Hope (Patricia Polacco retells the story of the 1991 firestorms and weaves in a tale of religious diversity, with the Sukkot holiday and families coming together in crisis).

California Museums (photos from the firestorm)

City of Oakland (firestorm history)

San Francisco Local (20th Anniversary commemoration, including information on firestorm emergency preparedness, how the community has changed in response to the firestorm.)