Storm blow for market gardeners

Vegetable growers are facing crop damage after last week's thunderstorms, which delivered up to 96mm of rain in just three hours to areas south of Perth.

Baldivis grower Sam Calameri received more than 60mm, which slammed part of his carrot crop.

"Because so much rain fell in such a short space of time, the ground wasn't able to take it in," he said.

"A lot of ground has flooded and washed away and the crops were flattened by the rain.

"We will lose quality and yield on 10 hectares of young carrots emerging from the ground."

Mr Calameri said the full extent of the damage would not be known for about three months when his carrots were harvested.

"We will have to grade heavier at harvest time to get good quality," he said.

"Our wastage will jump by about 20 per cent. A lot of the carrots are going to be deformed and twisted."

Mr Calameri said power outages caused by the storm had affected his operations.

"We had power failures and the cool rooms went out," he said.

"The power went out on Friday morning and came back on Saturday, but we were able to repair the cool rooms fairly quickly."

Nearby grower Mark Gasper reported damage to his parsnips after 96mm of rain fell on Friday morning.

"There was one (quarter-acre) planting of parsnips which suffered, because they were just germinating," he said. "Parsnip yields will be down by at least 40 per cent and I am waiting to see whether I should plough them in or not.

"We had a bout of hail which lasted for about 20 minutes - that caused the most damage. A tree was uprooted and a power pole came down."

But Mr Gasper said his three-hectare onion crop was unscathed.

He said he got off fairly lightly from the unprecedented rain event.

"I've never seen anything like it in my whole life," he said. "To have that much rain come at once with thunder and lightning was pretty horrifying. There was some damage but it could have been a lot worse."

Mr Gasper said the rains would benefit some of his crop.

"It was helpful in some ways because it's brought the alkaline and salt levels down in our soils."

Bureau of Meteorology climate and weather information officer John Relf said a trough and mid level disturbance brought about the storm.

"The worst of the weather was to the south of Perth, including eastern areas," he said.

"Chidlow had 86.4mm of rain from the storm and Mandurah had 56.6mm, followed by a 10mm rain event. Mandurah recorded 24mm in 27 minutes between 5.53am and 6am, so it was a high concentration of rainfall in a short period."

Wind gusts of up to 80km/hduring the storm caused power outages and there were reports of lightning strikes from the event.