Dull CA pattern; fire season heating up inland

While the current weather pattern along the CA coast better  resembles “June Gloom” than the typical heatwaves of August, the fire season across inland areas and more interior states of the West has intensified quite a bit in recent days. Of immediate note is the Zaca Two fire currently burning in Santa Barbara County. The Zaca fire has been burning for nearly a month, and, as many of you may remember, firefighters had almost reached containment on the fire about 2 weeks ago. A spot fire escaped containment lines, however, and in the past week the fire has burned another 30,000 acres for a total of nearly 60,000. State and federal fire officials are extremely concerned about the potential of this fire to cause damage and casualty for several reasons. Firsty, the heavily forrested area in which the fire is burning has been untouched by fire for over 100 years. There has been no thinning of undergrowth, and all of this undergrowth (and many of the trees, as well) are extremely dry–live fuel moistures have been measured at historically low levels. Secondly, the terrain is extremely steep and rough, which makes it difficult not only for firefighters to access the fire but also increases the volatility of an already explosive fuel bed and the risk of catastrophic uphill runs. The Santa Barbara County Mountains are also susceptible to Sundowner Winds, some of which may occur this week. Thirdly, the fire is surrounded in all directions but south by heavy forest for at least dozens of miles, which means the fire has essentially unlimited fuel and space to burn. Parts of this forest have been affected by bark beetles, which have led to vast stands of dead pine trees. Directly to the south of the fire lies the city of Santa Barbara, which could be directly threatened by the Zaca fire. Santa Barbara has had a history of fire disasters (recall the mission there), so there is currently great concern that flames could encroach on the city in the coming days and weeks. Also of concern: in the next 4-8 weeks, we will enter Santa Ana season. If there is a strong offshore wind event at any point before a season-ending event (significant, widespread rainfall) occurs, the fire has the potential to burn at a rather astonishing rate of several thousand acres per hour for brief periods of time. Stay tuned…we’re going to be hearing a lot more about this one.

As if that weren’t enough, the situation fire-wise is actually a lot worse currently in Montana and Idaho, where at least 10 fires of 50,000 acres or more are less than 20% contained. Nearly all of these are direct threats to life and property, especially in the relatively heavily populated parts of the Bitteroot Valley, and are not expected to be contained or controlled until a season-ending event occurs (at least October in those more northerly locations). All this considering the West is actually rather cool currently, with an unusually active and southerly Pacific jet for summer creating aclimatological troughiness along the West Coast and bringing miserable and even dangerous heat to the eastern 2/3 of the country. If a more “summerlike” weather pattern does take hold over the West, such as a rebuilding of the Sonoran heat ridge, there will be a further increase in fire activity.

Note: over on the forums at www.wildlandfire.com , several fire managers have voiced the opinion that the Zaca fire could end up being the costliest and largest fire in (state, or possibly even in national) history. Stay tuned.

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