'We can no longer be friends': Farmer warns climate change deniers, after storm devastates crop

Ben Lehmann says neither he nor his father had seen a storm this intense in their lifetimes. (Supplied: Jo Lawler)

Storms have devastated more crops in South Australia's mid north, prompting a farmer to publicly declare he was cutting social ties with any climate change deniers.

"This is the anxiety farmers now have to live with every day as these intense storms become more routine."

Mr Lehmann said neither he nor his father had seen a storm this intense before.

"We have to accept that many things are out of our control … but today has been the hardest day of farming in my short career," he said.

The hail not only snapped wheat plants but also knocked their valuable grain onto the ground.  (Supplied: Ben Lehmann)

Mr Lehmann said it was devastating to lose up to 100 per cent of crops in certain parts of his property so close to harvest.

"They're just a standing stalk and it's shredded complete heads on the ground," he said.

"It almost looks like a mower's been through it. You wouldn't put a big mob of sheep or cattle over it and it wouldn't look that bad."

Climate researchers say CSIRO modelling indicates hail storms, like that which struck farms in Caltowie, and droughts will become more intense in the future.  (Supplied: David Hodgson)

Fellow Caltowie farmer James Moore said about 25 per cent of his property was affected and that in some paddocks he thought he had lost up to 80 per cent of his barley.

Mr Moore said with grain prices high and good seasonal conditions it was frustrating to lose crops only 10 days before harvest.

"It was very annoying. Dad and I were saying the other day that we were amazed with how good the year was looking and how good the prices were," he said.

Weather events predicted to be more extreme

Rain hits Renmark and flash flooding affects Whyalla on Saturday. (ABC News)

University of Southern Queensland climate researcher Roger Stone said it was difficult to attribute any single event to climate change, but it is interacting with naturally occurring weather patterns and making them more extreme.

He said the recent severe storms were mainly a result of the annual La Niña event occurring later than usual.

La Niña is the result of the warm water around northern Australia interacting with cooler sea temperatures in the eastern Pacific Ocean which cause volatility in the spring.

Hail thrashed Ben Lehmann's property at Caltowie, among others.  (Supplied: Ben Lehmann)

"Unfortunately it's developed at exactly the wrong time of year for our harvests around the country."

Professor Stone said CSIRO modelling has shown for many years that more intense drought and hailstorms can be expected in the future.