While some companies and entities with outdoor workers are wisely suspending their outdoor operations during the deep freeze gripping part of the nation, others don’t have that option.

Police officers and firefighters throughout the U.S. remain on the job, answering calls and patrolling as usual. Towing companies are especially busy, since the frigid temperatures are wreaking havoc on car engines and necessitating more jump-starts or tows. Zookeepers are tending to the animals in their care, who must eat even when it’s cold. Parking lot attendants aren’t finding much warmth in their booths, but they’re faring better than valet parkers, who spend a good deal of time outdoors.

Letter carriers for the United States Postal Service are not making their appointed rounds in a number of states, due to the weather.

The sub-zero conditions are expected to ease – somewhat – tomorrow, according to weather forecaster. Until then, residents in the Great Lakes region in particular will be exposed to a high risk of frostbite and hypothermia. The cold has so far been blamed for nine deaths.