Came across an oddball tip that's a cheap way to make snow tires for bicycles
The basic idea is, wrap zipties around the tire/wheel. Each ziptie would be done to to around the tire/rim so that the tie forms a line straight across the tire. It looks like approx 20-30 zipties per wheel. The "nub" part of the ziptie can be carefully positioned to be an extra grip on the road surface.
Where I live (cough cough) doesn't have the weather to have to experiment with this. It'll have to be someone who lives in a place with real weather.