It came as the Met Office issued Scotland’s first severe weather warning of the autumn for ice for that area for Sunday night.
The Maritime and Coastguard Agency said it had been asked to send teams from Aberdeen, MacDuff and Stonehaven to support the Police Scotland operation on the River Don at Monymusk, north east of Aberdeen.
The woman is believed to have got into difficulty while attempting to rescue a dog. A Police Scotland spokesperson said: “Searches are ongoing. We have nothing else to add.”
Monymusk Parish Church minister Euan Glen has announced a candlelit vigil for the woman, who he referred to as Hazel, in the church at 6.30pm on Sunday.
The Met Office yellow warning for ice last from 8pm on Sunday to 9.30am on Monday for most of Aberdeenshire and Angus, Aberdeen and the eastern edges of Moray, Perthshire and the Highland Council area.
It said: “A much drier and colder night than of late with a frost developing quite widely over Scotland and ice likely to form on untreated surfaces.
"The north east of Scotland will see the greatest ice risk, where surfaces are still wet from recent rain and run off from fields and higher ground. Fog or freezing fog patches are also likely to form overnight which will add to the difficult traveling conditions.”
Temperatures are expected to fall to -4C in places such as Aboyne and Huntly in Aberdeenshire.
The alert followed a yellow severe weather warning for heavy rain for eastern Aberdeenshire and Angus until 3pm on Sunday.
Eight flood warnings were also in force on Sunday across the area as well as in Perthshire and Orkney. They covered the River Don in Kintore, the South Esk near Brechin, Brothock Water in Arbroath, three on the River Isla around Coupar Angus, the River Earn south of Perth and the Churchill Barriers in Orkney.
Inspector Rory Campbell from Police Scotland said on Saturday: "Conditions are tricky and dangerous and I am appealing to members of the public to stay away from flooded areas.
The Scottish Environment Protection Agency said Brechin river levels on the South Esk reached their highest on record, while in Ballater the River Dee reached the second highest level ever.
ScotRail reported no weather-related disruption to trains on Sunday after significant problems on Friday and Saturday.
Meantime, Moffat and Strathclyde Police mountain rescue teams helped recover an injured paraglider who had dislocated his knee when he was dragged along the ground while trying to take off from near the summit of Tinto Hill in South Lanarkshire on Saturday.