Should California get more tropical storms like Hurricane Hilary?
What Made Hilary a Grinch? Why Hurricanes Move into the Southwest US This Weekend and It’s Not Just Another Scattered Tropical Storm
California is notoriously dry this time of year. There were some desert areas that received more than a year of rain over a single day this weekend.
When Tropical storms arrive in a place unaccustomed to them, they are usually less prepared. Even though a tropical storm that hits California might be weaker than storms that frequently roll through Gulf Coast communities, the lack of preparation can lead to outsize impact. If there are not proper building codes and if there is a lot of development in flood-prone areas then the risks could be greater.
There will not be a lot of hurricanes moving into the southwestern US in the future. But when they do happen, they’ll be much more like Hilary,” says David Easterling, chief of the Climate Assessments Section and director of the National Climate Assessment Technical Support Unit at NOAA’s National Centers for Environmental Information.
What made Hilary—which began life as a hurricane in the eastern Pacific—so gnarly? Simply put: Warm ocean water fuels hurricanes in the tropics. Warm, moist air at the surface of the sea rises, and the surrounding air rushes in to fill its place, creating winds. “The winds at the surface of the ocean pick up energy in the form of moisture and heat,” says climate scientist Karthik Balaguru, who studies hurricanes at the Pacific Northwest National Laboratory. “This air spiraling in toward the center of the storm, if it carries more moisture with it, once it rises it is able to release more latent heat energy. This process restores order to the storm.
Like wringing out a great big sponge in the sky, starting this weekend tropical storm Hilary dumped an incomprehensible amount of water on Mexico, Southern California, Arizona, and Nevada, breaking “virtually all rainfall daily records,” according to the National Weather Service. In California, Mount Wilson got more than 8 inches of rain over the course of two days. In Beverly Hills, there have been more than four inches of rain in just one day.
The remnants of that storm are moving across Nevada today, where the Las Vegas Valley Water District issued a boil water order for some residents because of flooding.
Plan for Tropical Catastrophes. The Disaster of Hilary in San Juan, California, Overshadowed by a Tropical Cyclone
Pita says that preparing for storms is worth it even if they’re not frequent. “It’s a spectrum of actions that need to be done in time, not just in desperation right now. We need to plan in advance.
Hilary has caused flooding and debris flows which destroyed homes and businesses as well as overwhelming people in their cars. The mayor said there was a very extreme situation at the moment, as of Monday morning.
The officials are only estimating the damage. And while it will take some time for scientists to fully work out how much climate change contributed to Hilary’s destruction, such storms will likely get more and more ferocious as the world warms.
Every two to three years on average, though, a hurricane forms in the eastern Pacific and “recurves” north toward Mexico. When it makes landfall, it loses that source of moist heat energy from the ocean and dissipates. (Hilary was downgraded to tropical storm status by the time it made landfall in Baja California, and it is now a post-tropical cyclone as it moves through Nevada.) The storm’s remnants may travel into the southwest US and interact with mountains.
