The wall in Douglas St collapsed before 4pm, leaving a tree, dirt and debris scattered across a section of footpath.
Denise Fraser, who lives about two doors away from the affected property, said the wall was down when she returned home about 4pm.
By 3.30pm State Highway 1 was closed between Horsnells and Old Ferry Rds in Waimate, and by 4pm the Timaru District Council had declared a state of emergency and was warning residents to prepare to evacuate.
Emergency operations centre controller Justin Bagust said people in particularly flood-prone areas should be making preparations in case they had to evacuate at short notice. An NZ Transport Agency spokeswoman warned people to avoid all travel between Dunsandel and Oamaru, including on local roads and highways.
"Many parts of the road are near impassable and conditions are treacherous," she said.
Roads might be closed at short notice, she said.By 5.30pm a section of State Highway 1 at Showgrounds was impassable and a detour was in place. The absence of traffic prompted Timaru man Daniel de Garnham to venture out in the floodwaters in a kayak, complete with lifejacket, observed by his friends.
MetService continued to issue a "severe" weather warning for parts of the South Island late yesterday.
A spokesman said people who had to travel should check the weather forecast and the NZ Transport Agency’s traffic and travel webpage for the latest information on road warnings and closures.
- Alexia Johnston
