The strong and unusually high winds hit Kurnell just after 10.30am on Wednesday along with heavy rain and hail the size of golf balls. Photo / Twitter / @BOM_NSW
Sydney's desalination plant has been damaged and three people are injured after a tornado tore through the city's south with winds of more than 200km/h.
The desalination plant in Kurnell was evacuated after reportedly sustaining significant damage and workers were also cleared out of the Caltex refinery.
The strong and unusually high winds hit Kurnell just after 10.30am on Wednesday along with heavy rain and hail the size of golf balls.
A second storm cell was moving north up the coast and expected to hit Wollongong around 12.30pm.
A 40-year-old man suffered head injuries in Kurnell and ambulance NSW said officers treated two other people.
They were all transferred to Sutherland Hospital in a stable condition.
Sydney airport was closely monitoring the storm activity with passengers being advised to check flight details with their airlines, an airport spokeswoman said.
Qantas has delayed some flights until the storm clears up.
An eyewitness in Sydney airport says a number of Jetstar flights have been cancelled.
A balcony in Maroubra in Sydney's eastern suburbs collapsed and the roof of a unit was damaged as storms travelled north.
Jenny Zhou, who works at the local Friendly Grocer in Kurnell, said the roof leaked and the shop flooded.
"I think about 10am, a big storm came," she said.
"There is water everywhere .. all through the shop."
Beth, who lives and works in Cronulla in the city's south, said "golf ball-size hail" fell on St Andrew's Anglican Church.
"We had some brown-outs, lots of thunder and lightning, and some large hail," she said.
"The wind was strong and it was hitting our glass windows. I have a big dint in the front of my car."
State Emergency Services are advising residents to secure their homes and to remain indoors.
BOM will issue another weather warning shortly.
Some 7000 businesses are without power, including Kurnell Public School.
The SES has received over 160 call outs, with 65 from the Sutherland shire.
Kurnell's Bridges St has been particularly hard hit with a number of homes suffering significant damage, a Fire & Rescue spokeswoman told AAP.
BOM issued a midday warning for a severe thunderstorm which is due to hit the Blue Mountains and Hawkesbury regions within the following hour.
• A violently rotating column of air, in contact with the ground, often visible as a funnel-shaped cloud.
• Rare in Australia but can happen with almost any severe thunderstorm, and occur most commonly in late spring and summer.
• Range in size from a few tens of metres across to around a kilometre in diameter.
• Between 10 and 20 are sighted in Australia every year.
• 364 tornadoes have occurred across NSW from 1795 to June 2003.
• Need intense, sustained updraught.
• Strong change in wind speed and/or direction.
• Strong winds at cloud-top level.
• Mostly near the back of a thunderstorm, usually to the west.
• Heavy rain and hail first.
• A violent wind lasting from several seconds to two minutes as it passes.
• While you can hear sounds caused by damage, many tornadoes are silent.
• After storm, some light rain or hail can occur, along with cooler winds.
• Weak tornadoes are most likely during mid-summer thunderstorms, but can occur during winter months in southern Australia. Strong tornadoes typically happen with late spring/early summer.
• Tornadoes travel with a thunderstorm cloud at about the same speed and direction - around 30-50km/h.
• If a vigorous cold front is near, they may reach speeds of 80-100km/h.
• Once formed, their motion is dependent on the movement of the parent thunderstorm.
• Generally agreed they don't exceed 450km/h.
• Victorian State Emergency Services were prompted to issue a tornado warning after severe storms and flash flooding hit the northern suburbs of Melbourne on November 5. No major damage occurred.
• Severe thunderstorms brought on a mini tornado in western NSW on August 25, hitting Dubbo in the late afternoon. Some properties were damaged by the tornado.
- AAP
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