Driving too fast for existing weather conditions = involuntary manslaughter.
Firetruck only has so much hose, especially if you are the 1st or second one to show up. Ya gotta get at least that close. Probably had at least one bright as hell flashing LED strobe, AND its huge and painted red, not to mention the other firefighters all in breakout gear with reflective tape covering them, oh and a car accident disrupting the normal traffic flow with one of them actively on fire.
If you are asleep and doing governed speed down the interstate, none of that matters.
In Virginia, state law REQUIRES drivers to yield right-of-way (move over to the next lane), or slow down to a crawl if you can't, when approaching "stationary emergency vehicles". Judging from the condition of the truck, the driver didn't slow down, or move over, and hadn't adjusted speed in consideration of the poor driving conditions. Regardless of the weather, there are enough reflective materials and flashing lights on a fire truck to see it.