Hurricane Hilary, currently a Category 4 storm, is forecast to bring heavy rain and potential flooding to parts of the Southwestern U.S. this weekend into early next week.
Moisture associated with Hilary will start streaming into the region over the next few days. However, the main impacts are expected Sunday into Monday as the hurricane interacts with the Southwest.
Forecasters warn that Hilary could dump more than a year’s worth of rain over parts of Arizona, Nevada and California. The National Weather Service has issued a Level 4 threat for excessive rainfall — the highest threat level — for Southern California. This is the first time such a high threat has been issued for this area.
In Arizona, the most rain is expected across the western third of the state. The National Weather Service has issued Flood Watches across many areas of Arizona in anticipation of excessive rainfall. Northern and Northwestern Arizona are also under Flood Watches thanks to monsoon moisture that could bring heavy rain even before Hilary arrives.
Parts of California like the Coachella Valley are under Tropical Storm watches, with the National Weather Service warning of potential high winds and extreme flooding rain that could force evacuations and rescues.
Overall, those in Southern California, Nevada, and Western Arizona should prepare for the risk of widespread flooding, several inches of rain, high winds and even potential evacuations in the hardest hit locations. Residents are advised to have emergency supplies ready and monitor updated forecasts closely over the weekend. Dangerous, life-threatening conditions are anticipated from this rare tropical system making landfall so far north and west.
Hilary Draws Comparisons to Hurricane Doreen (1977) & Hurricane Nora (1997)
Hurricane Hilary has the potential to be the first tropical cyclone to make landfall in Southern California since Hurricane Doreen in 1977.
Doreen brought heavy rains, flooding and mudslides to areas like San Diego County, killing one person. Hilary poses a similar threat with its abundant moisture tapped from the tropical Pacific.
Farther east, the remnants of Hurricane Nora in 1997 soaked Arizona, causing extensive flooding and damage comparable to a Category 1 hurricane. Nora’s heavy rains led to record flooding along rivers and washes, destroying homes and infrastructure. Hundreds had to evacuate the town of Yuma, which received 3.59 inches of rain.
On a more westerly track than Nora, Hilary is unlikely to unleash Nora-like flooding dangers in Western Arizona as current modeled forecasts show precipitation totals of just over an inch for Yuma. However, the deserts of Southern California are likely to see Hilary create conditions similar to what Nora produced in Arizona.
Overall, meteorologists see similarities between Hurricanes Doreen in 1977 and Nora in 1997 and the current forecast track and moisture feed from Hurricane Hilary. Though the storms are decades apart, their rare paths from the Eastern Pacific into the Southwest could produce analogous hazards ranging from damaging winds to catastrophic inland flooding.
Officials urge vigilance this weekend into early next week as Hilary interacts with the Southwest states, where tropical cyclones of this magnitude are infrequent.
Cover photo courtesy of: Midjourney