This hairy little guy had crawled in under the sill of the front door, presumably looking for a warm dry place to pass the winter. I reckon it’s a the caterpillar of Ruby Tiger Moth (Phragmatobia fuliginosa) rather than that of an Ermine Moth, based on the lack of visible pale stripes and the dark colouration with tufts of paler hairs. I relocated him to a safer spot, so hopefully he makes it through the winter.