Extreme heat — like the record-breaking heat wave that’s been scorching Southern California for weeks — is a growing health hazard across the nation, according to the National Weather Service. It’s the No. 1 cause of weather-related deaths in the U.

S., more than hurricanes, flooding and tornadoes combined. But for L.

A. County’s unhoused population, who live under conditions where water, shade and showers are already scarce, the health risks associated with the heat are even worse . “Everything is exacerbated in the heat,” said Sade Kammen of Water Drop Los Angeles, a nonprofit that provides drinking water to unhoused people on Skid Row.

“People are just lying on the pavement in their underwear anywhere they can find shade. They just look exhausted. Many are passed out in their tents.

” Classic heat stroke signs — confusion, dizziness, headaches, fainting, delirium and lethargy — often go unnoticed among this group, reducing the chance of intervention, according to recent studies. Some people are at even greater risk because of pre-existing health conditions. Studies show that many medications and recreational drugs increase the risk of dehydration and heat-related death.

Last week’s unprecedented heat wave broke National Weather Service Records in many cities across California, including the L.A. County cities of Lancaster and Palmdale where temperatures soared above 110 degrees.

Several fatalities and illnesses across the West have been linked to the h.