Late last week, Phoenix, Arizona, experienced scorching temperatures exceeding 40 degrees Celsius, marking a highly unusual event for March. This heatwave is part of a broader pattern of extreme weather across North America and beyond, with significant implications for public safety and infrastructure.
Record-Breaking Heat in the Western US
In Phoenix, temperatures soared to a record-breaking 40.5 degrees Celsius on March 20 and 21, a level typically not seen until late May. The National Weather Service highlighted the anomaly, noting that such readings are rare for this time of year, with the last occurrence of 100 degrees Fahrenheit in March dating back to 1988. This week, temperatures are expected to remain in the high 30s Celsius, underscoring the persistence of the heatwave.
Across the western United States, daytime maxima have exceeded climatological norms by more than 15 degrees Celsius. For instance, Denver, Colorado, reached 30 degrees Celsius on Saturday, a first for March and the city's highest March temperature since 1971. Forecasts indicate that daytime highs will approach 30 degrees Celsius again this week, driven by high pressure anchored over the region, which is likely to spread eastward by Thursday.
Arctic Blast Hits Canada
In stark contrast, Canada is bracing for a sharp drop in temperatures as Arctic air surges southward. Enhanced by the high pressure over the western US, this cold plunge is pulling polar conditions into Canada, with temperatures expected to fall more than 10 degrees Celsius below seasonal averages. Major cities like Saskatoon, Saskatchewan; Quebec City, Quebec; and Edmonton, Alberta, could see maximum temperatures as low as -9C, -7C, and -6C respectively on Thursday and Friday, with daytime highs struggling to rise above freezing.
Storm Therese Disrupts Canary Islands
Meanwhile, the Canary Islands faced severe weather as Storm Therese swept through late last week. Tenerife was particularly hard-hit, with authorities declaring a state of emergency and issuing orange weather warnings. Northern areas experienced wind gusts of about 60 mph, while the south saw heavy rainfall, with some locations recording up to 100 mm. The storm also brought snow to higher elevations, leading to flight cancellations, school closures, and the deployment of over 1,000 emergency personnel. Although conditions have calmed, unsettled weather with heavy showers and thunderstorms is expected to continue, potentially bringing another 90 mm of rain through Thursday.
Analysis and Implications
This juxtaposition of extreme heat in the US and cold in Canada highlights the volatile nature of current weather patterns, likely influenced by a meandering jet stream. Such events underscore the growing frequency of climate anomalies, posing challenges for emergency services and public health. As high pressure spreads eastward, monitoring and preparedness will be crucial to mitigate impacts on communities and infrastructure.
