There is a lot of talk recently about how “extreme” the weather is now, and how it will get so much more “extreme” in the future (even more specualtion here). There are certainly some robust theories as to why this will happen – why the frequency of severe weather events might increase (like all time heat records) - and we should of course be sure to keep our eyes open and do what we can to survive extreme weather events (like burying electrical lines, also see Superstorm Risks). However, we should remember that some unbelievably ”extreme” weather has happened in the past.
There has been much talk about how the desert southwest of the U.S. is going to suffer from more heat and drought in the future. The odds are fairly good that this will happen, not only if the global climate continues to warm, but also for the plain fact that there are millions and millions more people living in, and moving to, the southwest, creating greater stress on the water supply and adding more to the urban heat island effect. However, a “mega-drought” in the southwest should not come as too much of a surprise to blog readers here because I have detailed the climate history of the southwest a couple of times in the past. As new research also shows, multi-year and multi-DECADE droughts were common a few hundred years ago. So there is a fairly good chance we could see some “extreme” stress on rivers such as the Colorado, but it will probably not as extreme as what happened during past mega-droughts. The 20th century might turn out to be an anonymously wet period – and the “extreme” drought might be just “getting back to normal”.
Citicorp Center had to be reinforced in 1978
Even as extreme as Superstorm Sandy appeared, it was known that such a storm was possible decades before, and that infrastructure would be in trouble. La Guardia airport had flooded before and Sandy-type storm surges had been modeled. The Citicorp building was even vulnerable at one point if a “big storm” ever created high winds in New York. Around other coastal areas of the U.S. there have been many periods where stronger hurricanes have struck the coast, well before Katrina entered our collective memory.
One would think receiving 50 inches of rain over just a few days would be pretty extreme as well, but looking at today’s date in weather history we find that it happened in southern California way back in 1969:
On this day in 1969, a spate of heavy rain begins in Southern California that results in a tragic series of landslides and floods that kills nearly 100 people. This was the worst weather-related disaster in California in the 20th century.
Although January typically features relatively high precipitation in Southern California, the first month of 1969 saw an extraordinary amount of rain throughout the region. Mt. Baldy, east of Los Angeles, received more than 50 inches in the nine-day period beginning January 18. By January 26, the Federal Emergency Management Association (FEMA) had declared it a federal disaster area.
The worst part of the remarkable rainfall was that it caused a series of landslides in the hills of Southern California. In Glendora, 1 million cubic meters of rock and mud slid down a hillside, destroying 200 homes and killing dozens of people. Although there was only one fatality, the plight of Mandeville Canyon, north of Sunset Boulevard in L.A.’s Brentwood section, during the disaster was heavily publicized due to the wealth and fame of its residents….read the full story here.
I can’t imagine all of the press and “hyperventilating” that would occur if 50 inches of rain fell in the mountains around Los Angeles in the present day, but it is certainly possible again. The oceans are a bit warmer and that means more moisture will typically be available for Pacific storm slamming into California. By the way, on the topic of landslides, a recent report found that it is a more dangerous “weather event” than most people realize.
We might have different types of extreme weather or more frequent severe weather in the future, but a lot of it has occurred before. Our short memories need a refresher once in a while.
Have a nice Friday! Meteorologist Justin Loew.
Posted under AGW, Climate Change, Drought, Flooding, Heat, Severe Weather
This post was written by jloew on January 18, 2013