An autopsy is scheduled to be conducted on a homeless man, found wearing only a T-shirt and shorts over the weekend in Hayward, to determine if hypothermia played a role in his death.
If the frigid temperatures did play a role, the 50-year-old man would be the sixth case in the Bay Area since Thanksgiving to be linked to hypothermia-related homeless deaths during the region's cold snap, with temperatures dropping to near- and below-freezing levels over the last week.
PHOTOS: Extreme Weather 2013
Homeless people across the United States are facing similar, if not worse, situations. In Oklahoma, where temperatures were the 20s over the last several days, homeless advocates worried about those sleeping in tents instead of shelters.
"I haven't seen so many cases in such a short time frame," Santa Clara County Sheriff's Lt. David Lera, who oversees the coroner's office, told NBC Bay Area on Monday. "It's not uncommon for a hypothermia case to come through, but that's usually out someone hiking. It is unusual to have so many homeless deaths in such a short time period. It's a public safety risk."
According to a 2010 report from the National Coalition for the Homeless based in Washington, D.C, about 700 homeless people are killed from hypothermia each year.
But since the Bay Area is not as cold as the East Coast or other parts of the country, hypothermia is not a household word. And dying from the cold is certainly not an everyday occurrence.
Hayward Police Sgt. Ken Forkus said it is still too early to tell what caused the homeless man found Sunday in the courtyard of the old City Hall behind a Safeway store to die. But he did acknowledge the temperatures were low and the man was not dressed for the proper weather conditions.
Over the weekend, the Alameda County coroner determined that a homeless man found dead early Friday morning in Dublin died of cold-related issues.
And on Friday, the Santa Clara County Coroner's Office announced that four homeless men in their 40s and 50s died at various encampments in the South Bay - the first one reported on Nov. 28.
Three of the deaths occurred at various homeless encampments in San Jose, according to officials, and a fourth victim was found dead in Saratoga inside an open garage. Those victims were identified by the medical examiner's office in San Jose on Monday.
The deaths sent homeless advocates and other community leaders scrambling to get out the word about open shelters and doing more to protect those most vulnerable to the cold.
Freeze warnings are expected through Tuesday morning, with temperatures dipping to 27 degrees in the North Bay and reaching about 38 degrees in San Jose. The cold snap is expected to break later in the week, with highs reaching in the mid 50s. Saturday and Sunday could reach the low 60s.
Names of victims' whose deaths were related to hypothermia:
• Daniel Brillhart, 52 years old, died on 11/28/2013, location of death: Delmas and Auzerais in San Jose
• Enrique Rubio, 56 years old, died on 12/04/2013, location of death: 600 Block of Lincoln Ave in San Jose
• Andrew Greenleaf, 48 years old, died on 12/05/2013, location of death: 20000 Block of Orchard Road in Saratoga
• Daniel Moore, 53 years old, died on 12/05/2013, location of death: Curtner Ave. at Canoas Gardens in San Jose