Winter Storm Hernando swept across north-eastern parts of the US on Sunday and into the start of the week, bringing a blizzard to large parts of the region as heavy snowfall combined with gale-force winds. Blizzard warnings were issued for major cities including New York City, Portland and Boston, while more than 10,000 flights were cancelled and schools closed across several states. The storm intensified rapidly through Sunday, with coastal areas of Massachusetts and Rhode Island recording wind gusts of about 70mph, and Montauk Point in New York reporting stronger gusts of 84mph.
By Monday, snowfall totals had exceeded 38cm (15in) in parts, including Central Park and John F Kennedy international airport. Some communities experienced more than six consecutive hours of steady snowfall, with totals surpassing 76cm in parts of Massachusetts and on Long Island, New York. Rhode Island recorded as much as 96cm by Monday night, while Fall River, Massachusetts reached 1o4cm, making it one of the most significant snowstorms since 2016.
At the height of the storm, more than 650,000 homes and businesses were without power. Although the worst conditions eased by midweek, lighter snow, sleet, and freezing rain lingered into Thursday and Friday. At least two deaths were attributed to the severe weather.
The storm has been described as a “bomb cyclone”, which is derived from the term “bombogenesis”, and occurs when a mid-latitude storm rapidly intensifies and drops its central pressure of at least 24 millibars within 24 hours. Hernando’s pressure reportedly fell by about 40 millibars in less than 12 hours, signalling explosive development. The rapid deepening was fuelled by a sharp contrast between relatively mild, moisture-laden Atlantic air and much colder continental air from Canada. The strong temperature gradient strengthened the storm’s circulation, while abundant moisture led to intense snowfall, with slightly warmer air enabling heavier, wetter snow and substantial accumulations.
Meanwhile, an unusually slow-moving weather system has unleashed days of torrential rain across central Australia, drenching vast stretches of the Northern Territory, South Australia, Queensland, and New South Wales. Rain and thunderstorms linked to the stubborn low-pressure system have lashed these areas since early this week. At Nappa Merrie in south-west Queensland, more than 165mm fell in just 24 hours on Wednesday, which was an extraordinary deluge in a region that typically records 100-200mm of rain across an entire year. The system is expected to linger over the interior of the country until at least Saturday, raising the prospect of further heavy rainfall and renewed flood concerns in already saturated areas.
