Are Fire Seasons New?

Fire season is a concern for all on the West CoastFire season is a concept we are familiar with in the West Coast, but it may be foreign to those moving here or living far away.

Not long ago I was on the phone with a cousin from the East Coast. That area had recently been hit by Tropical Storm Ida and over here we were being smothered by the smoke from the Northern California fires (Caldor, Dixie, Tamarack and some others). Aghast at enormity of it all, my cousin asked the poignant question, “has there always been a fire season, or is that a recent thing?”

Fire Season

Briefly, yes, California has always had a fire season.

One major reason people (myself included) love California is for its mostly dry Mediterranean, subtropical climate. However, that ideal dry hot summer climate is also a perfect tinderbox. Without summer rain, the grasses and annuals die off and many native perennials go dormant. Dry hot winds, frequent from around August through October, dry out the landscape even more. By this time, an open hillside is A-grade kindling – one little spark and it’s a recipe for disaster.

Even in wet seasons with no drought, the summer will always be hot and dry with a high risk of ignition. So while fire season is nothing new, it’s longer and much worse than it used to be.

Fire and California Homes

For California homeowners and buyers, the increasing fire danger is strongly felt. Most buyers tell me they do not want to be in high fire risk zones, but might not always know what to avoid. State and local governments have put more preventative regulations in place to keep homes safe from wildfire, both on builders and homeowners.

If you are relocating to Silicon Valley, you may be wondering what the risks of wildfire are like for this area. There are plenty of resources available online, and I always recommend clients to look at the hazard maps such as those listed in my article Tools You Can Use When Relocating to the San Jose Area. While the mountain and foothill communities may be at risk of wildfire, even the lowlands are experiencing another concern that comes with harsher fire seasons: smoke and air quality.

In my other blogs I have more articles dedicated to the topic, so I won’t go into detail here. I encourage you to view some of my articles about Fire at the Live In Los Gatos Blog or over at the Valley of Heart’s Delight blog under the Natural Hazards and Safety categories if you’re interested in learning more.

Some of the oldest trees living in California have the scars of past fires, sometimes multiple. Native plants have evolved and adapted to fire and can thrive in its shadow. And for as long as people have lived here, they have contended with seasonal fire danger.

Fire season 2021 has come to an end with the arrival of rain – a double bounty since we are in the middle of a severe drought. When the rains come, the problems aren’t over, though. In burned out areas, the next challenge will be mudslides and further damage to the fire zones. This is an old problem also, I remember hearing about the mudslides following the fires as a kid growing up in the 60s and 70s.

Fire hardening” is an important concept for those of us who live in or near large open spaces with hills especially. I suspect it will grow into a cottage industry with new experts appearing to advise or possibly install features which will make our homes and landscaping more resistant to advancing flames.

Smoke and air quality

August 2021 - smoke and air quality in Los Gatos are impacted by the Caldor and Dixie firesFire season has been getting longer in Silicon Valley, and with it are smoke and air quality issues.  The  Bay Area is full of micro climates, and that translates to areas which are more or less impacted by these problems.

  • windier areas, where the breeze blows from the San Francisco Bay or the Monterey Bay to inland areas may have the cleanest air if the fires generating the smoke are far away
  • lower elevation areas may have less smoke if the blazes causing the smoke are far (distant fires seem to cause the smoke to be higher up)

Weather patterns, smoke and air quality

Please note, I’m not a meteorologist, but am going to share my observations from living here most of my life (except a few years from 18-23, I’ve been in this area).

Our Silicon Valley weather is dominated by the nearby Pacific Ocean. Most of the time, the coast enjoys foggy mornings and sunnier afternoons, and the inland areas are impacted by that. When the coastal overcast burns off, clouds recede from the Monterey Bay.  In the mid to late afternoon, winds reverse, and breezes pick up. This is also true with winds coming off the San Francisco Bay and moving south along the Calaveras Mountains.

Wind patterns are key for the discussion around smoke and air quality.

Most of Silicon Valley is in the Santa Clara Valley. Valleys can trap air in what is called a heat inversion at times (a warm area prevents the air below it from moving around – we see this in winter sometimes). When that happens, we get a “Spare the Air” day and are asked to do what we can to help the air pollution problem. The coastal areas don’t have this issue, so usually don’t have smog. They have plenty of wind from the ocean. If there is a fire elsewhere in California, most of the time it does not impact the coast to the same degree as the inland areas.

As a general rule, when the fog is pushed in from the Pacific, it comes through any low points or passes it can find. The foggier areas to the north of Silicon Valley, such as Daly City and San Francisco, don’t offer much resistance to the push from the Pacific. Nearly always, coastal wind means cleaner air. (more…)