I have previously railed against the state’s Travel Map, which is supposed to let out-of-state visitors know whether they can enter Vermont without self-quarantining. Roll the tape, please.

C’mon, now. Do you really expect out-of-staters to look up and obey this map? Which, by the way, changes weekly — so don’t pre-plan a visit for two or three weeks from now, because your county might turn yellow or red.

That was just one of multiple objections to the map. But finally, I’ve found a way in which it’s legitimately useful: it quantifies our collective feeling of dread.

Looking at multiple maps in sequence shows how the virus is spreading, and illustrates exactly why Gov. Phil Scott finally imposed a mask mandate. The map above was released on June 30; here’s the July 10 version.

As a reminder, each area is a county. “Green” counties have low Covid rates, so their residents can travel to Vermont without restriction. But on July 11, there was already a lot more yellow and red, and a lot less green, than on June 30.

Now here’s the latest version, released on July 31.

That’s a little scary. In five weeks’ time, the red zone has been moving steadily northeastward. It now includes all of Delaware, most of Ohio, Virginia, Maryland, and New Jersey, large chunks of Pennsylvania and West Virginia, and half of Rhode Island. Connecticut and Massachusetts are almost entirely red or yellow. The two red blotches along Vermont’s southeastern border are Albany and Rensselaer Counties, a mere hop and a skip from Bennington.

That right there tells you why we now have a mask mandate even though our own caseloads have held steady. That’s why educators are dubious about in-person schooling, and why faculty and staff are leery of reopening our institutions of higher learning. That’s why people like me, in the high-risk demo, are limiting time away from home and staying out of any indoor space that might have more than a few people in it. (When I have to hit the supermarket, I’m there right at 7:00 a.m. I still haven’t had a haircut, and haven’t been in a restaurant since early March.)

Coronavirus is on the move, and it’s headed our way.