Heatwave sweeping United States kills 10 police dogs

The heatwave sweeping the United States has claimed more casualties, this time 10 police dogs.

The soaring temperatures have even proved too much for cactus plants in Arizona. And there are concerns air conditioner use in New York could overwhelm the power grid.

Casualties of the heat, 10 of the 19 police dogs travelling in the back of a truck overheated and died when the air conditioning failed without the driver realising.

The working German shepherds were being transported to a canine training facility in Michigan City. The surviving dogs exhibited symptoms of heat stroke.

"They were up and alert but clearly suffering," one person said.

Air conditioning failure is also a major concern in New York. The city's utility company is asking residents to watch how much they're using because of the impact on the power grid.   

"Everyone is using their air conditioners, and what it can do is it can overheat our system and that can cause outages," said Alfonso Quiroz, spokesperson for Con Edison.

It's a major worry for New Yorkers who are desperately looking for ways to beat the heat.

"I am concerned because if the power goes out, you know, my mom is elderly, so the AC blowing out would not be OK for us in the heat, especially like the kids too," one local said.

Temperatures across the US are so high even notoriously 'sun-loving' plants are struggling. In Arizona, cacti are dying. Phoenix has spent a month enduring temperatures over 40C.

While in California, an unlikely visitor decided to take a dip in a pool. The homeowner spotted the bear enjoying a five-minute cool plunge before it climbed a nearby tree and fell asleep.

Even the animals are struggling to cope. But there could be some relief with forecasters picking the heat may have peaked for large parts of the country.