With an Arctic blast set to bring sub-freezing temperatures to the Philadelphia region, Montgomery County and Philadelphia declared "Code Blue" emergencies.
The Philly alert -- issued by the city's Homeless Services Office -- goes into effect at 6 p.m. Wednesday while the Montgomery County Commissioners' declaration takes effect at 9 p.m.
"A Code Blue Cold Weather Declaration is made in Montgomery County when winter conditions pose a threat of serious harm or death to individuals without shelter," the Montco statement said. "A Code Blue is called when the combination of air temperature and wind chill is anticipated to be 20 degrees or less."
Philly issues under similar circumstances and uses it so that the city's homeless outreach can increase staffing to get more homeless people into shelters.
Montco's declaration is set to expire at noon Saturday as temps are expected to warm above freezing. The Philly declaration last until 6 a.m. on Dec. 21.
Camden County also issued a Code Blue warning for 6 p.m. to 6 a.m. Wednesday into Thursday and Thursday into Friday.
NBC10 First Alert Weather chief meteorologist Glenn "Hurricane" Schwartz issued a warning of his own -- a First Alert.
"The wind chills here will be in the single digits from Thursday morning through Friday around noon. That’s more than 24 straight hours! The coldest it should feel is near zero during Thursday night," Hurricane wrote in his blog post.