Tumbarumba, already hit by fire, named in severe thunderstorm warning

The Bureau of Meteorology issued the warning just before 4pm, advising Tumbarumba, Cooma, Bredbo, Adaminaby, Nimmitabel and Khancoban are likely to be affected as the front moves through.

Areas expected to be impacted are the Snowy Mountains and parts of the south coast, south west slopes and Australian Capital Territory forecast areas.

The Dunns Road fire has more than doubled in size since 9am on Tuesday, growing to more than 54,000 hectares in size.

The region is already subject to a BoM fire weather warning.

Move your car under cover or away from trees

Secure or put away loose items around your house, yard and balcony

Keep at least 8 metres away from fallen power lines or objects that may be energised, such as fences

Report fallen power lines to either Ausgrid (131 388), Endeavour Energy (131 003), Essential Energy (132 080) or Evoenergy (131 093) as shown on your power bill.

Unplug computers and appliances.

Avoid using the phone during the storm

Stay indoors away from windows, and keep children and pets indoors as well

For emergency help in floods and storms, ring the SES (NSW and ACT) on 132 500