Weather forecasts for Southern California are beginning to look alarming this weekend, as Hurricane Hilary will cross central Baja California and its remnants will plunge headlong into California’s Colorado and Mojave Deserts, and then on into the Great Basin. Lots of rain for dry western deserts (sorry Phoenix), but also lots of destructive flooding.
A pessimist looks at Hurricane Hilary and offers his advice.
There are only two good paths that Pacific hurricanes can follow to get close enough to the U.S. to make a major impact: along the Gulf of California (Sea of Cortéz), or by hugging the western Baja California coast and taking full advantage of what warm water there is there. Hilary is taking the second path.
Other storms have tried to make it (I was SO excited by Nora in 1997, but it exhausted itself before reaching the Colorado River valley). Hilary looks like the real deal, however.
Halfway up the Baja coast the water abruptly turns chilly, and a tropical storm will rapidly disintegrate, but if it’s big enough and moving fast enough it might retain enough power to make an impact. Hilary is big enough and moving fast enough.
Hilary will disintegrate over the driest deserts in North America (Colorado, Mojave); deserts that are underlaid by water-impermeable caliche soil, and are thus incapable of quickly absorbing large amounts of water. Raging torrents are inevitable. It will be scary.