For California Flood Preparedness Week, Drew Ready talked with the National Weather Service’s Eric Boldt about the wild weather we’ve had this summer and fall. Read on…
Hurricanes that battered Baja California brought large surf and rain to the region this summer and fall. On August 4th a 500 year storm brought walls of water, mud, and debris flows through several canyons in the eastern San Gabriel Mountains.
We are quick to forget that wild weather is not uncommon this time of year. In the summer of 1939, seventy five years ago this year, Los Angeles was suffering from a ten day heatwave (over 90 died) when on Monday, September 25 remnants of a Pacific hurricane slammed into Long Beach and Los Angeles. Thunderstorms brought 5.25” of rain to Los Angeles in 24 hours, Mt. Wilson recorded 11.6 inches. The Los Angeles River broke its banks and 45 were killed. Gale force winds and huge surf capsized boats along the coast where another 48 died. Because of this storm and deadly storms in 1938, agencies deemed the LA River too dangerous and restrained it with a concrete straight jacket.
We know tropical hurricane driven summer storms happen from time to time in Southern California, but could there be a correlation between climate change, El Nino, and recent record setting weather? We took a few moments to talk with the National Weather Service’s Warning Coordination Meteorologist Eric Boldt who provided these insights.
CWH: Southern California received more rain in August and September than usual this year. Under Climate Change can we expect more of these storms and summer precipitation?
Eric Boldt: I don’t think there is any correlation between Climate Change and tropical storm precipitation. The research has stated that due to more water vapor in the atmosphere, a result of higher carbon dioxide levels, we do see more intense rainfall across the majority of the country when it rains. There is research suggesting that warming the atmosphere will lead to more intense storms, including hurricanes, but more research will be needed.
CWH: Is climate change to blame for recent and extreme low and high rainfall years (~38” in 04/05 and only ~3” in 06/07)?
Eric Boldt: …the main correlation between Climate Change and rainfall is the intensity of rain will be higher, I don’t think the research has said much about the frequency of high or low rainfall years. There are climate models suggesting that the Southwest will likely see more droughts and longer duration droughts in the future. These high/low rain years are more a reflection of longer term climate cycles from ENSO (El Nino Southern Oscillation) and other atmospheric circulations (PDO, PNA, etc.). Flash flooding and daily rainfall records are more likely to occur in the future due to Climate Change.
CWH: Is there a correlation between the weak to moderate El Nino this year and the tropical storm/summer rain events this year in Southern California?
Eric Boldt: The eastern north Pacific has been warm since last winter and the majority of the eastern Pacific continues to warm due to the developing El Nino-like sea surface temperatures. It is typical to see more tropical cyclones in the eastern Pacific during El Nino fall months. It has been quite active for cyclones to form off the Central American coast and track northwest toward Baja this summer and that has resulted in above normal rainfall for the Southwest.
Thank you Eric! We are fortunate to have such an authority on weather in our region. If you are in the LA area, be sure to sign up for updates from Eric and his team at the National Weather Service . But just because September has passed, don’t think we’re out of the weird and wild weather woods yet, October has caught us off guard once or twice too.
