Hilary surged towards Southern California as of 6 a.m. local time on Sunday, with the region preparing for perilous flooding and dangerous winds. The storm was projected to lose its hurricane status upon making landfall, yet it is anticipated to yield far-reaching and severe consequences for California, the Desert Southwest, and Mexico’s Baja California. Millions of individuals are currently under a tropical storm warning, marking the first instance of such an alert hitting Southern California in over eight decades.

Late on Saturday, Governor Gavin Newsom (D) declared a state of emergency for a significant portion of Southern California.

Key Points to Note:

• A tropical storm warning is now active for both the coastal and inland areas of Southern California, including San Diego and Los Angeles. This warning is the inaugural one issued for this location by the National Hurricane Center.
• Forecasters are being straightforward about the impending danger presented by the storm, particularly its potential for causing floods. Authorities are urging the population to prepare.
• The National Hurricane Center cautioned on Saturday that “catastrophic and life-threatening flooding is likely over Baja California and the Southwestern U.S. through Monday.” Since Saturday night, there has been a consistent occurrence of light to moderate rain over Southern California. While no flood warnings were in effect as of early Sunday, this is anticipated to change.
• The National Weather Service issued an early-morning bulletin, highlighting that “scattered to numerous areas of flash flooding are likely to develop as Hurricane Hilary accelerates northward along the Baja California coast.”
• It was noted in the bulletin that atmospheric moisture levels were already at record highs in Yuma, Arizona, and Las Vegas. These levels were projected to rise even further.
• Rainfall rates were expected to be 0.5 to 1.0 inches per hour until midmorning, followed by an increase to at least 1 to 2 inches per hour, according to the Weather Service. As a result, significant instances of flash flooding could emerge, particularly on the eastern and southern slopes of mountain ranges in Southern California and western Nevada. Currently, Southern California has received between 0.1 to 1.0 inches of rain, with the highest amounts occurring in the interior. These totals are set to rise when the core of Hilary passes by on Sunday afternoon and evening.
• Flood watches along the Mexico border in Southern California and Arizona extend northwards to Oregon and Idaho. Flooding rains are also impacting the western coast of Mexico’s Baja California.
• Despite the storm’s rapid movement, its speed won’t prevent substantial rainfall. The Weather Prediction Center noted on Sunday that “there is a very real potential for 3 inch amounts in an hour in this environment.” Southern California, along with southern and central Nevada, is projected to receive 2 to 4 inches of rain, a quantity equivalent to a year’s worth for parts of the typically arid region.