At 5:30 a.m., when the world was still dark and brittle with cold, someone started pounding on my front door hard enough to shake the frame and echo through the house. I had already been half awake because the wind howled through the old maple trees outside, and my weather app warned the temperature had dropped to minus thirty eight degrees with wind chill.

I pulled on a robe, hurried to the door, and opened it to a blast of freezing air so sharp it stole my breath and made my eyes water instantly. On my porch stood my grandmother, Dorothy Caldwell, seventy eight years old, hunched into herself inside a thin beige coat that clearly was never meant for weather this brutal.