UPDATE, 3:54 pm: The number of people who have died in Portland from hypothermia in the first 10 days of 2017 has reached four.

An unidentified 29-year-old man was found dead this morning in the woods below Southwest Barbur Boulevard. Portland police announced this afternoon that he died of exposure to the cold.

They believe he was living in the woods. Police will not release his identity until they have informed his family.

Portland is expected to get three inches of snow tonight. Here's a full list of cold-weather shelters that are open.

ORIGINAL POST, 12:38 pm: Reports of two homeless people dying of hypothermia in Portland in 2017 have shaken the city.

The deaths of Mark Eliot Johnson on an East Portland sidewalk on Jan. 2 and Karen Lee Batts in a downtown parking garage on Jan. 7 have raised questions about the city's ability to protect its neediest citizens during a cold snap.

In fact, three people have died of hypothermia in Portland this year—and the trend started on New Year's Day.

David B. Guyot, 68, was found at a bus stop downtown, and died of hypothermia-related causes at Emanuel Hospital on Jan. 1. He is believed to be homeless at the time of his death.

Oregon Public Broadcasting first reported Guyot's death on Monday, in a story on how Batts was evicted from her apartment.

All three deaths have been ruled as hypothermia cases by the Multnomah County Medical Examiner's Office.

"The harsh reality is that dozens of people are dying on our streets in Multnomah County every year," says Israel Bayer, editor of Street Roots. "And the cold weather has created a nightmare scenario for people sleeping outside."

Hypothermia deaths are typically rare in Portland.

Multnomah County officials, who track homeless deaths in the annual "Domicile Unknown" report, say they identified no deaths from hypothermia in 2015 or 2014, and just one in 2013.

In a 2010 report, the advocacy group National Coalition for the Homeless reported that 700 people experiencing or at risk of homelessness die from hypothermia annually in the United States.

Hypothermia occurs when someone's core body temperature falls below 95 degrees F, and is associated with exhaustion, numbness, confusion, and organ failure, which can lead to death.

Hypothermia becomes a risk at temperatures below 50 degrees Fahrenheit, but according to research by the National Coalition for the Homeless, many homeless shelters don't start cold weather services until it is much colder.

Temperatures in Portland dropped to as low as 15 degrees over the past week, before rising above freezing on Jan. 8.