Tornadoes strike Detroit and east coast as heatwave blankets US south-west | Extreme weather

A two-year-old boy was killed and his mother critically injured after a fast-developing tornado struck and caused a tree to fall on their home in the suburban Detroit city of Livonia on Wednesday.

Meanwhile, tornadoes also struck in Maryland on the east coast and a brutal heatwave affected the south-west and California as extreme weather continued to mark the start of summer in the US.

The Livonia fire chief, Robert Jennison, said the tree, described as “massive”, landed on a bed where the child and his mother were sleeping. The mother is in critical condition in hospital; a two-month-old who was also in the home is expected to be OK.

“I’ve been here 35 years. I’ve never seen a storm come through like this. It’s devastating, it’s horrible to see,” Livonia resident Melanie Ricketts told CBS News Detroit.

The storm that produced the tornado came without “advance warning” from the National Weather Service, the city said in a statement. “A representative from the NWS called it a spin-up storm which didn’t show up on their radars in enough time to issue a warning,” it added.

Five hundred miles away, in Gaithersburg, a Maryland suburb north of Washington DC, a separate tornado stuck two homes. In one, four people had to be extricated, including one who was “pinned and removed” by emergency services. At the other, a tree trapped a resident who had to be rescued.

Video of the tornado in Montgomery county showed a large, cone-shaped funnel suggested a strength of at least a two out of five on the Fujita scale – an intensity more common to the Great Plains and south than the mid-Atlantic region.

The last tornado in the region to reach that strength was in 1996.

“I’ve lived here 75 years and we’ve never had nothing like this come through Gaithersburg,” Jacqueline Harding told the Washington Post. “Nothing that would tear trees down and stuff. Not this bad.”

Mariela Cabanillas, a Gaithersburg resident who sheltered in a basement, told the outlet that the tornado had hit “really quick, I think in those moments you don’t really understand what’s happening until it’s over”.

Outbreaks of tornadoes accompanying intense storms in mid-Atlantic and northern states is commonly attributed to rising global atmospheric temperatures.

Excessive heat warnings extended from the Central valley of California down through southern California’s deserts, parts of Nevada and Arizona, and into Utah. In total, the warnings affected more than 29 million people.

On Wednesday, the EU’s climate change monitoring service said that each of the past 12 months ranked as the warmest on record in year-on-year comparisons. The UN secretary general, António Guterres, called for urgent action to avert “climate hell”.

The average global temperature for the 12-month period to the end of May was 1.63C (2.9F) above the pre-industrial average – making it the warmest such period since record-keeping began in 1940, the Copernicus Climate Change Service said.