BY MIKE MAGEE
On September 25, 1939, Southern California woke with worry of The Lash of St. Francis or El Cordonazo on the horizon. The time period refers to northwestern monitoring, cyclone-laden storms that may hit the western shores of Mexico and California mostly across the Feast of Saint Francis, on October 4th. This one made landfall at San Pedro, California.
The calamity that day in Southern California was a uncommon occasion, the one certainly one of its type within the twentieth century. The final one to hit, previous to this was in San Diego on October 2,1858. The Earth’s rotation usually assures that such cyclones on this area transfer from east to west, and out to sea. However the 1939 storm was the exception, and the massive drawback was the rain, some 5 1/2 inches over a 24-hour interval (although the city of Indio, within the Coachella Valley of Southern California’s Colorado Desert area skilled 7 inches and buried the valley in 4 ft of water. Forty-five died on land, and 48 perished at sea. One optimistic – the storm marked the tip of a 1-week warmth wave the place Los Angeles reached 107 F levels and claimed 100 lives.
Historical past repeated itself 84 years later this weekend, with a memorable “Lash” on the backend of a summer season warmth wave. The human, financial, and ecological tolls stay to be calculated. However one factor is for sure, world warming has arrived, and with it the manufacturing of each warmth and water and a brand new, all too acquainted meteorological phenomenon, the “atmospheric river.”
NOAA defines “atmospheric river” this manner: “Atmospheric rivers are comparatively lengthy, slender areas within the environment – like rivers within the sky – that transport many of the water vapor outdoors of the tropics. Whereas atmospheric rivers can range significantly in measurement and energy, the common atmospheric river carries an quantity of water vapor roughly equal to the typical move of water on the mouth of the Mississippi River. Exceptionally sturdy atmospheric rivers can transport as much as 15 occasions that quantity. When the atmospheric rivers make landfall, they usually launch this water vapor within the type of rain or snow.”
To be clear, these drenching above-ground collections of water are typically a blessing as a result of they supply many of the much-needed precipitation to California’s dry areas and replenish the water cycles within the area. However because the Earth has warmed, they extra ceaselessly symbolize “an excessive amount of of a great factor”, and at the moment are chargeable for 90% of California’s flood harm.
NASA reports that “the will increase in water vapor are a consequence of worldwide warming. Greater temperatures enhance the evaporation of water over land and sea. The hotter space holds onto extra water vapor, and slows down condensation and precipitation. The trapped water floating within the sky absorbs much more warmth, which in flip attracts much more water vapor – making a disastrous “optimistic suggestions loop.”
By sucking up water vapor, the phenomenon makes dry areas drier, and by forming and dumping the “rivers”, creates wetter moist areas and tragic flooding. Particularly, listed below are five predictable repercussions of human behavior-induced alterations in world atmospheric well being.
1. Heavier Rainfall: For each 1 diploma Celsius (1.8 right here F) rise in atmospheric temperature, the air is ready to soak up 7% extra water. Because the pre-industrial revolution, the atmospheric temperature has risen 1.3 levels Celsius. By the tip of this century, if pattern traces are uninterrupted, rainfall quantities may enhance as much as 60% over present ranges.
2. Huge Infrastructure Destruction: Flood harm within the billions is almost sure as storms develop into extra intense, extended, and nearer spaced. Atmospheric river occasions may enhance three or four-fold in comparison with pre-industrial occasions. Anticipate an extra $1 billion in flood harm for each 1 diploma Celsius rise in temperature.
3. Diminished Snowpack Reserves: Atmospheric rivers are related to much less snowfall in western U.S. mountain ranges. Intense rainfall on current snow accelerates melting and excessive flooding from speedy water runoff. Termed “rain-on-snow” occasions, areas at biggest threat are the Canadian Rockies, the Sierra Nevada, and the Colorado River community.
4. Geographic Shifts: Hotter atmospheres present indicators of altering the jet stream, pushing it nearer to the equator. Consultants have predicted that this can consequence within the winter growth of atmospheric river occasions in Southern California. Paradoxically, soils are drying out as a result of elevated soil evaporation, much less snowpack cowl, and erosion from speedy downpours.
5. Lack of Sea Ice: Recent studies reveal that shrinking ice cowl within the Artics is just not merely a perform of warming temperatures. A brand new contributor is that the atmospheric rivers are more and more shifting north towards the Arctic Pole. It’s now believed that the resultant water on ice is chargeable for not less than 1/3 of the lack of winter ice. They do that not solely by the melting impact of direct water on ice over 10 days following every downpour but additionally by magnifying “downward longwave radiation”
As this most up-to-date climate calamity confirms, human-instigated excessive climate-driven occasions at the moment are inescapable within the quick time period. This storm is presently dumping 3 to six inches throughout the area, with 10 inches in some areas coming near overwhelming the deep LA water trenches. Equally evident is that our trendy (and getting old) infrastructure – together with roads, spillways, bridges, dams, constructing codes, and rescue and security operations – require a speedy redesign.
Mike Magee MD is a Medical Historian and common THCB contributor. He’s the writer of CODE BLUE: Inside the Medical Industrial Complex.
