Perth awoke on Thursday to a thick blanket of fog, prompting warnings for motorists to exercise caution. The fog was visible from as early as 4am local time and persisted into peak hour, severely limiting visibility on several roads.
Humidity reached 99 per cent at 1am and remained at 93 per cent by 8am, creating the foggy conditions. The Bureau of Meteorology said fog may be present in parts of WA's South West Land Division, with high humidity stretching from the northern Wheatbelt to the edge of the Goldfields.
Main Roads urged commuters to use caution on the Tonkin Highway, the Narrows Bridge, and the Mitchell and Graham Farmer Freeways. Reports of fog came from City Beach, Mt Helena, Malaga and Banksia Grove.
Fog forms when air cools overnight, causing humidity to reach 100 per cent and excess moisture to condense into tiny droplets. The Bureau of Meteorology noted that fog is most common in valleys and forms under clear skies with no wind.
A man believed to be in his 60s was taken to Royal Perth Hospital after a crash north of Perth. A car and a truck collided around 7.15am near the Chittering Roadhouse on the Great Northern Highway. The man was trapped in the wreckage and rescued by crews using hydraulic equipment. Main Roads reported reduced visibility in the crash area.
