Despite relatively warm temperatures following the extreme lows of Jan. 6 through 7, experts say residents should keep in mind that winter could still have more in store for Carroll.
According to Rich Foot, founder of the Foot's Forecast weather analysis collective, the so called polar vortex that brought zero degree temperatures to Carroll County earlier this month was caused by multiple high pressure systems that emptied a reservoir of extremely cold air from north-eastern Canada by channeling it into more southern climes.
"It was a cross polar flow situation where multiple cold fronts channel the cold air and it brings anything else that's cold with it -- from the pole, from Siberia -- pulling it all the way into central north America," Foot said.
Foot said that while much of that arctic air was exhausted in the process, the reservoir is currently being replenished and though it is unlikely the country will see lows quite as extreme as during the polar vortex event, there is still plenty of cold left in the atmosphere. This is important given that Jan. 15 through Feb. 10 is a climatologically favored time period for snow storms.
"We still haven't had a traditional, classic snow event yet, where you get the coldest air, the snow comes and then it's cold after the snow and everything cools off, getting really cold for several days," Foot said. "We could easily still be talking about single digits."
Beyond making residents uncomfortable, the extreme cold of the week of Jan. 6 also lead to a vast amount of vehicle trouble for Marylanders, according to AAA Mid-Atlantic auto club Spokeswoman Christine Delise.
"AAA Mid-Atlantic dispatched over 7,500 requests for service in Maryland, which reflects a 425 percent increase compared to the 1,400 requests by motorists in Maryland during the same time frame in 2013," Delise said.
Delise said that during the spike in service calls between Jan. 6 and 8, the most common reason for calling were vehicles needing towing and vehicles with dead batteries, though it's likely many of the tows requested were due to dead batteries or under-performing batteries.
"According to AAA's Automotive Research Center, at zero degrees Fahrenheit, a car's battery loses about 60 percent of its strength and at 32 degrees Fahrenheit it loses 35 percent," Delise said. "During cold temperatures starting an engine can take up to twice as much current as needed under normal conditions."
According to Ben Perricone, territory manager for the AAA Approved Auto Repair Program of AAA Mid-Atlantic, temperatures that are significantly below freezing can adversely affect vehicles on multiple levels.
"Anytime the temperature goes below freezing, problems will start to arise," Perricone said. "Coolant and windshield washer fluid will freeze if they are not in proper concentrations, and batteries lose a lot of their starting capacity at or below freezing temperatures ... the increased viscosity of cold oils makes the demand on starters greater, placing an even larger demand on batteries."
Perricone said that even motorists who had no difficulty earlier in the month should consider having cold weather maintenance done on their vehicles to ensure their smooth operation through the rest of the winter season.
"Just because a vehicle made it through [the Polar vortex] with no issues is no guarantee that the vehicle would survive a subsequent cold spell," Perricone said.
He recommended having car batteries "load tested" to ensure they will generate enough current to start a vehicle in freezing temperatures, checking tire pressure as cold temperatures can cause tires to lose air and also checking the levels and consistency of coolant and other fluids.
"A proper 50/50 mix of coolant and water will provide freeze protection to about [32 degrees below zero]," he said. "Fluids such a brake fluid, transmission fluid, differential and transfer case fluid -- for four wheel drive -- should be checked to ensure quality and correct quantity. For example, brake fluid is hydroscopic, meaning it will absorb water from the air. Over time the buildup of water can degrade the quality of the fluid to the point it could freeze in cold temperatures."
According to Foot, his team believes Carroll will likely have at least a few more snow events this winter, and while none are likely to exceed six inches in snowfall, snow cover will contribute to lower temperatures. He said the polar vortex would have been even colder had previous snowfall persisted until the cold front swooped in.
"Boy, we were lucky we lost the snow cover," Foot said. "We didn't get the subzero temperatures we expected because the warm rain washed away the snow cover and took way that additional cooling effect."