Weather tracker: North-west US hit by snow ahead of eastern heatwave

Unseasonal snow has fallen in some parts of the US, while other parts of the country brace for a heatwave this week. A strong cold front spread into the western US from the northern Pacific over the weekend, bringing an abrupt change in conditions to a region that had been experiencing high summer temperatures amid drought. Temperatures from the Canadian border to California have widely been 5-10C below the norm since Friday, and more than 10C below in some parts farther north. The pattern is expected to remain for much of the coming week. The cold front brought the first significant rainfall in weeks to several parts of the north-west US. Across the Rocky mountains in Idaho, Montana and Wyoming, this combined with the unseasonal cold to produce snowfall at unusually low elevations for the time of year. Whereas the snow line in summer typically sits at about 3,300 metres (11,000ft), snow fell as low as 1,800 metres on Sunday, with more due to fall on Monday. Several inches are expected to accumulate at higher altitudes. Counterintuitively the cold front has also strongly increased the danger posed by wildfires. With much of the western US currently suffering some form of drought, lightning strikes from the leading edge of the front posed an ignition risk to the widespread dry vegetation and plant litter, while heightened winds fuelled the spread of existing fires. Firefighters watch as the Cottonwood fire burns near Beaver, Utah, on Saturday. …