Squalls are the worst. They come with little notice and can lay down 2 inches or more of snow in an hour over a relatively short distance of road.
Unlike major storms, which are forecast well in advance, with squalls the salt trucks typically don't get put into action until the damage is done.
By then, if it's especially cold, as is often the case, the intense snow is soon ground into ice by heavy traffic on major highways. Inevitably, accidents, a lot of them, are the result.
I've been lucky over the years, living in Maryland where such conditions are not common. The few times I've encountered them here, I recognized what was happening and applied knowledge gained from years of winter driving in NEPA as a college kid.
For those less experienced, I'd advise taking the first exit off the highway and waiting the situation out -- because squalls rarely last more than 90 minutes.
We actually ran into this a month or so ago on I-81 north of Harrisburg on our way to visit one of our kids. That stretch of road between Ravine and Hazleton is notorious for bad driving conditions in winter, even as early as November.
Anyway, a bad squall came up on a 50-mile stretch of road and laid down 3-4 inches of snow in the space of two hours. A rapid series of accidents led the police to shut down the highway. We sat a couple hours on a local road near Pine Grove before things opened up.
At the end of the day, no matter how experienced you are, it sometimes comes down to luck. Wrong place, wrong time sort of thing.
