This week, the state of California is experiencing wildfires and a record-breaking heat wave. This weekend, an incoming hurricane could bring heavy rains and flooding. “It definitely feels like a lot of everything at once, that’s for sure. And that’s true in many areas right now, not just California,” Daniel Swain told As It Happens host Nil Köksal. “And many of the things that are happening are exactly the kinds of events that climate science has long predicted would increase rapidly in a warming climate,” said Swain, who is a climate scientist at the University’s Institute for Environment and Sustainability of California, Los Angeles. On Tuesday, the state capital of Sacramento, along with six other places, set all-time high temperature records. Sacramento reached 46.7 degrees Celsius, while Santa Rosa recorded a higher temperature of 46 degrees Celsius. A wildfire in the northern part of the state in and around the town of Weed has left two people dead and destroyed hundreds of homes and other buildings. Two more people died and a third was injured in a wildfire in southeast Los Angeles that is still only about 5 percent contained, according to the state fire marshal. Hurricane Kay is expected to move up Mexico’s Baja California peninsula and come within 300 kilometers of San Diego, Swain told Köksal. The following is part of their conversation. A person uses a piece of cardboard as a shade on the Santa Monica Pier amid intense heat in southern California on September 4. (Mario Tama/Getty Images) The words historic, record — we hear them, you use them, when we talk about climate stories. It can be difficult for people and desensitization, I think, at some point to give them a sense of what we’re dealing with. But as a climatologist, what are you seeing and feeling this week that is shocking even to you? It was notable on several dimensions, not least for the maximum magnitude of the heat, which in some places broke not only the all-time September monthly records, but also the all-time temperature records from any month in places like Sacramento and parts of the interior San Francisco Bay Area. But it was also a very protracted event. This is now a full week of extreme heat. And in some places there are at least a few more days. This is a very long heat wave for a place where summer heat waves are often broken by a sea breeze after a day or two. This event had no such relief. it just goes on and on. And the other aspect, too, is that the overnight temperatures were extremely warm. California often sees heat waves where temperatures, at least overnight, drop to more manageable levels, which allows people and buildings to cool. In fact, this is one of the reasons why air conditioning in some parts of the state is relatively uncommon. There was the ability to just open the windows and turn on the fans and bring in that cool air at night. But during this particular event, some places stayed record warm at night in the 80s and even 90s Fahrenheit, straight through the night. Residents watch as a plane drops fire retardant over homes in Hemet, southeast of Los Angeles, on Tuesday. (Frederic J. Brown/AFP/Getty Images) And speaking of wildfires, new evacuation orders went into effect just this morning in parts of California. I understand from you, you think this heat may make even more fires possible in the coming days. We’ve definitely seen a big uptick in wildfire activity in the last week or so, coinciding with this extreme heat in California. But the other thing to remember, too, is that California’s fire season can, in many years, be very severe. So it doesn’t necessarily peak during the hottest summer months, but actually peaks later in the fall. So having this extreme heat event, which also resulted in this massive vegetation drying event, right before the autumn wind season is particularly bad timing. So it’s not just a question of the fires burning right now during the heatwave, but how that has set the stage for worse fires later this fall if and when those winds arrive before the start of the season. of rain. And to top it all off, there’s a hurricane off the coast. How will this affect things? Yes, this is very unusual, actually. California is not a place that sees hurricanes almost as a rule. And to be clear, the hurricane is not going to make landfall in California. But it will make a relatively close approach, moving northwest up the coast of Baja California [state] to Mexico, and finally arriving at a position within two hundred miles of the coastal city of San Diego. So this will make one of the closest approaches of any hurricane in living memory to California. So this is a very unusual event. The effects will mainly concern the rains. It may ironically increase fire danger in the early hours, as winds will increase dramatically before the rain reaches southern California. But then the risk would probably shift more to flash floods in the mountains and deserts. So the heaviest rainfall is unlikely to occur in major cities like Los Angeles and San Diego, but will occur in the desert southeast, places that in a typical year receive only an inch or two of rainfall. But from this one storm it can get as much as four or five or six inches. Thus, two to three times the average annual rainfall can occur in just a few days in the desert. Written by Andrea Bellemare with files from The Associated Press and Reuters. Interview with Daniel Swain produced by Chris Trowbridge. The questions and answers have been edited for length and clarity.
