Weather Tracker: Unseasonal storms hit parts of Pakistan and India | South and Central Asia

Unseasonably wet weather has hit southern areas Pakistan and northwest India on Wednesday, as heavy rain rolled in from the west, accompanied by thunderstorms, hail and strong winds.

Karachi, Pakistan’s largest city, was particularly badly affected, locally recording more than 50 mm of rain with winds of up to 60 km/h. Walls, buildings and a pedestrian bridge collapsed, causing flooding and power outages across the city. At least 18 people were killed and several more injured, many from structural collapses, with other deaths attributed to a fallen tree and lightning.

Storms were less intense for the neighboring Indian provinces of Gujarat and Rajasthan, with most areas receiving no more than 15 mm, although the city of Rajkot recorded 38 mm. However, disruption was still felt, with some power outages along with minor damage to trees and buildings. Of greater concern is the impact on local agriculture, with farmers expressing concerns about crop damage and disruption of approaching harvests.

Heavy rain is rare in the region at this time of year; the majority of the annual rainfall occurs during the monsoon between June and September. The average March rainfall in Karachi is 15.7 mm, and the month is usually one of the driest in northwest India: most of Gujarat usually averages less than 1 mm and large parts of Rajasthan no more than 5 mm.

Meanwhile, much of the western US has been hit by a heatwave that has intensified throughout this week, with temperatures expected to peak on Friday and Saturday. This heat wave was caused by a meandering jet stream and an almost stationary region of high pressure. These two atmospheric anomalies have caused a warm flow of air from the south to be trapped, and with clear skies the air is getting warmer as it is heated by the sun. This effect is also referred to as a heat dome.

Maximum temperatures will widely exceed 30C across the south-west, around 10-15C above the seasonal average. On Thursday, temperatures soared to 42.2C in Indio, California, with many individual stations also seeing March records broken.

Phoenix, Arizona is expected to see temperatures above 40C for three days in a row from Thursday to Saturday. That would shatter the city’s March record, and perhaps even surpass the April record in the process.

Denver in Colorado is expected to top 30C on Saturday, almost 20C above average temperatures for this time of year. This heat wave is expected to continue into next week and propagate eastward, bringing much of the US under unusually warm weather by the middle of next week.