Suburbs at risk

The Brisbane River has peaked at just over 4.45 metres, under the 1974 flood level, say authorities who are warning that this peak will still be devastating.

Premier Anna Bligh has warned that Brisbane residents will wake on Thursday to "shocking" flood scenes despite the peak being downgraded to below the 1974 peak of 5.45 metres.

She said Brisbane had developed significantly since 1974 and that there were many more built-up areas that would be affected by flooding now compared to then.

Click below to see a map of suburbs at risk, or already inundated by the Brisbane floods.

MAP: Suburbs at risk.

For more detailed flood modelling, visit the Brisbane City Council webstie below.

Brisbane City Council: suburbs at risk

For more detailed information on donations, roads, transport, volunteer efforts, and weather forecasts click here.

The Bureau of Meteorology (BoM) said the river level at 3.30am (AEST) on Thursday "was 4.45 metres and rising with the high tide".

"A peak slightly above this level is expected in the next few hours."

The bureau said earlier on Thursday that the downgraded peak, to below 5.0 metres, was due to releases at Wivenhoe Dam being reduced quickly during Tuesday night.

The bureau said river levels will remain high throughout Thursday.

Authorities had earlier expected the river to peak at 5.2m at the 4am (AEST) high tide on Thursday, down from an even earlier forecast of 5.5m.

ENERGEX said 125,000 homes and businesses would on Thursday be without power in southeast Queensland - almost 80,000 in the greater Brisbane area, 30,000 in Ipswich and surrounding suburbs, 4,200 in the Lockyer Valley, and pockets around Redcliffe, Gympie, Logan and the Sunshine Coast Hinterland.

Ms Bligh said it would still test Brisbane with flooding expected to affect 36,000 homes and businesses.

"Brisbane will go to sleep tonight and wake up to scenes that they have, many of them, never seen anything like in their lives," Ms Bligh told reporters late on Wednesday.

Suburbs expected to be affected by flooding include:

Albion, Auchenflower, Bowen Hills, Brisbane City, Bulimba, Chelmer, Coorparoo, East Brisbane, Fairfield, Fig Tree Pocket, Fortitude Valley, Graceville, Hemmant, Indooroopilly, Kangaroo Point, Lytton, Milton, Moggill, Murrarie, New Farm, Newstead, Norman Park, Oxley, Pinkenba, Rocklea, Sherwood, South Brisbane, Tennyson, Yeronga, Yerongpilly, Windsor, Wacol