What causes clouds like this?

I've never seen clouds like this before!

For context, I'm in the middle of Canada. The temperature is -8 Celsius (-15 with the windchill), partly cloudy, wind is S 19 km/hr, humidity 60%, air pressure is 102.8 kPa (all according to the Government of Canada weather site, right now).

I am not a meteorologist and have very little cloud knowledge. Can anyone tell me what could cause a localized cloud pattern like this? I'm just curious!