by Ken Donnell
In my recent Opinion commentary it was revealed that extreme climate change disaster events have arrived in Plumas County in the form of wildfires which have been repeated, can be analyzed, and can be mathematically documented as accelerating geometrically. This is basic, hardcore science. It is therefore reasonable that other forms of mega-disaster events could also hit northern California and Plumas County in the near future: flooding, more wildfire, seismic activity, and/or wind events.
My purpose in writing these comments is not to vanquish hope, but to rekindle our hopes on a foundation of reality. Our old realities have been reshuffled by the onset of undeniable extreme climate change events. We humans are a highly adaptive species, and we must now adapt to investigate, analyze, and plan for these new realities, which are a result of mother nature’s response to human overpopulation and overconsumption. Forethought and planning for such extreme disaster events could possibly save many local lives and resources.
Most institutional and governmental planning stops at the level of “100-year disaster events.” Fifty years ago, this was wise public policy. But if other mega-disasters in northern California follow the recent trend for wildfires, we may soon frequently experience 500-year or 1,000-year level disaster events. As with the recent wildfires in Plumas County, such disaster events can reach levels never experienced in our brief recorded history. These mega-disaster events are literally “beyond our imagination.”
As such mega-disaster events begin to occur more frequently across California, the USA, and the whole world, the resources needed to respond to, and recover from, such disaster events may become more scarce. This will be true for any backwater region like Plumas County, and will be especially true if there are simultaneous mega-disaster events in our region. Please imagine the consequences in terms of human displacement if a mega-flood were to hit Northern California at the same time as a major earthquake shakes the Bay Area. All of Northern California will be impacted by the flooding, and thousands, perhaps tens of thousands may be displaced. Then add another 100,000 persons displaced from the Bay Area. Disaster aid will be needed everywhere, but there simply will not be enough resources to cover every need. This is why I believe it is so important that we make plans to tend to much of our own needs during future disaster events. Help from the outside world may be very slow to arrive in Plumas County.
It is important to further explain that while climate disaster events are classified according to their “average cycle of occurrence,” the timing for such events is not always evenly spaced. Thousand-year disaster events do not necessarily occur once every thousand years. There is ample evidence that extreme disaster events occur in clusters. There might be ten 1,000-year floods in a specific region within a single decade, with no thousand years floods for the following 10,000 or 20,000 years.
A severe flood is high on the list for possible mega-disasters in northern California. The greatest mega-flood in recorded California history occurred in 1862, when downtown Sacramento was under 10 to 15 feet of water. In the spring of 1862, much of the Central Valley became “Lake Sacramento,” which was reported to have stretched 300 miles north to south, and 20 miles east to west. All of California, even in the southern regions of Los Angeles, experienced severe flooding in 1862.
Large floods in northern California are usually “rain on snow events.” A significant snow pack builds in the Sierra Nevada and Coast mountains, until a warm “pineapple express” series of storms comes in from the Pacific, and drops huge amounts of warm rain, which quickly melts all of the snow. Between the heavy rainfall and melted snow, all of central and northern California can be impacted by flooding. Roads and bridges will be washed away or covered by landslides, low lying neighborhoods and whole towns might be flooded, and many people will be displaced. Plus debris dams can form suddenly and create flooding in areas with little or no previous history of flooding.
One of the more recent large rain-on-snow flood events occurred during the New Years Floods of 1996. A pineapple express series of storms arrived while there was 4 feet of snow at elevations such as Bucks Lake. After five days of rain, the ground at these elevations was bare. The result was many slides, washed out roads, and damaged bridges. Parts of Plumas county were cut off from all ground transportation for up to a week. It was early enough in the water year that most reservoirs were low and able to receive much of the runoff. Levees mostly held in the Valley, but there was still some significant flooding south of Marysville.
The largest winter snowpack in recent memory occurred during the winter of 1993, when a series of snowstorms started right after Christmas and continued for six weeks. Elevations such as Bucks Lake received 20 to 25 feet of snow during these storms. The most recent flood was in 2016, which while significant, was much smaller than the flood of 1996. Even so, the upper spillway dam of Lake Oroville almost collapsed, which would have flooded out 180,000 downstream residents.
Now imagine having snowstorms like the winter of 1993, which are soon followed by a series of pineapple express storms as in 1996. The resulting flood could be 3 to 5 times greater than the flood of 1996. There would be huge amounts of damage in Plumas County, and all over northern and central California. This would probably include major failures of levees in the central valley, and perhaps even a dam failure. Many people, perhaps a hundred thousand or more, could be displaced. With so many other localities receiving equal or greater flooding, there would be no immediate relief supplies coming to aid us in Plumas County? How long would we need to rely on our own resources in Plumas county to survive such a disaster event?
And, of course, try to imagine the stress on our disaster recovery resources if a major urban earthquake occurs simultaneously with such a mega-flood. These sorts of extreme disaster scenarios, which were once unthinkable, are now increasingly possible given how extreme climate change has accelerated the potential occurrence of such mega-disaster events.
I hope that my assessments for the near future do not prove to be accurate. I have no desire to be a “doomsayer.” But the math clearly shows that the risk for such mega-disaster events occurring in Northern California and Plumas County is rapidly increasing. If such risks are increasing, we would be most wise to also increase our preparation to respond to such “biblical scale disaster events.”