The family, which includes four children, left Kalgoorlie Boulder, about 600km east of Perth, in two cars on Sunday and were driving 650km north east toward Tjuntjuntjarra, where they were to arrive on Monday.
They have not been seen since and serious concerns are held for the group which consists of two elderly male drivers, four children aged between 12 and 17 and an elderly woman.
WA Police said severe weather conditions on Wednesday morning meant helicopters and planes could not be used in the search.
"At this time, road conditions are dangerous, particularly in relation to the route we believe the people have taken," a spokeswoman said.
"As soon as the weather improves, an air asset will be deployed."
Search efforts were hampered by the conditions on Tuesday, as a plane looking for the group could only stay in the air for about an hour.
The missing group is reported to be travelling in a beige Toyota Landcruiser, registration number A683 and a white Mitsubishi Triton, registration number KBC8881.
The continued search comes as a major road connecting large parts of remote WA reopened after a weather-induced closure.
The Eyre Highway between Norseman and Eucla, in the Goldfields-Esperance region, was made accessible to vehicles on Wednesday.
Motorists have been warned to drive to the conditions and exercise caution as there may be water over the road.
Goldfields Highway between Rosslyn Mine Hill and Meekatharra has also reopened for cars and four-wheel drives.
Emergency WA reported that floodways and river levels may rise rapidly and cause damage to roads and bridges along with making driving dangerous.
"Take care on gravel and unsealed roads as they may be slippery and muddy, and you could get bogged," an alert read.
"If your car stalls in rising water, abandon it immediately and seek shelter above floodwater."
Residents in WA's north have also been warned to take action as moderate flooding is expected in Fitzroy Crossing in the Fitzroy River Catchment.
Minor flooding has hit Noonkanbah and may also take place in Looma and Willare, east of Broome.
People in Laverton, Balladonia, Cundeelee, Ilkurlka, Warburton, Yelma and Lake Carnegie in Salt Lakes District Rivers have been warned to "take action" as minor flooding continues.
Leonora Laverton Road remains closed in both directions between Laverton and Leonora along with the Trans Access Road.
A low pressure trough over central and far south-eastern Western Australia has resulted in thunderstorms and heavy rainfall.
Significant rainfall over the past few days has resulted in localised flooding and road closures.
Heavy rainfall and thunderstorms are forecast for Wednesday which are expected to cause further river and creek level rises and overland flooding.
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