Story highlights The heat-related deaths of two elderly people were reported in northern California

Excessive heat warnings have been issued for parts of California, Nevada and Arizona

San Francisco (CNN) The record-breaking heat roasting the West has killed at least two people.

A 72-year-old man and an 87-year-old woman died Monday in San Jose, California. Their deaths were attributed to the heat, Santa Clara County officials said.

"It is tragic when someone dies of hyperthermia since in most every case it could have been prevented," Dr. Michelle Jorden of the county's medical examiner office said in a statement. "Hyperthermia and heat stress happen when a body's heat-regulation system cannot handle the heat."

San Jose sweltered in record-breaking, 103-degree weather on Sunday, and the area is under heat advisory until 9 p.m. PT Thursday.

Large swaths of California, Nevada and Arizona are under excessive heat warnings as residents have endured stifling, triple-digit temperatures in the last few days. Parts of eastern Texas and New Mexico are under heat advisories.

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