It’s all about the cliché “highs and lows”, but in this case we’ll talk about “ridges and troughs”. Storms in the middle of the northern hemisphere (the latitude of the U.S., Canada, and Europe) move from west-to-east. Storms generally follow the jet stream, which does not make a straight path but rather curves up and down like a big worm. Where the jet stream dips down towards the south (trough), cold and snowy weather make skiers happy. Where the jet stream bulges up toward the north (ridge), skiers start thinking about mountain biking.