Water from the bank holiday storms is believed be the cause behind two large sinkholes to have opened up on busy town centre roads.
Yesterday, traffic was left queuing all the way along Greyfriars after a void opened up on the road, within yards of the town's bus station.
The 5ft-deep chasm became the third large hole to appear in the town in just over a week and is still cordoned off.
Just 200 metres away, Sheep Street is currently blocked off while Northamptonshire County Council contractors work on another deep sinkhole, which is preventing a through route to Campbell Square.
The authority, which looks after the town's roads, has confirmed both cordons will remain in place over the weekend.
A spokesman said: "Investigation works are underway after voids opened up in the highway in Sheep Street and Greyfriars, Northampton.
“It is believed that the defects may have been caused by the relatively recent heavy rainstorms.
“The safety of the public is of the utmost importance and until the areas are made safe Sheep Street will remain closed. It is hoped to keep two lanes running on Greyfriars for as much of the period as possible.
“Contractors will be working today and over the weekend with the aim to complete the works by Monday evening.”
Charlene Willsher, a recruitment consultant who works on Sheep Street, 30, said the sinkholes are worrying for the people who live and work nearby - as well as being inconvenient.
Workers there are currently unable to park their cars near the office, due to the sheer size of the hole.
"It's quite scary in a way," she said. "You don't expect a hole like that to open up. They can get worse very, very quickly.
"We are here working opposite, wondering whether this could happen underneath the building here."
A spokeswoman for Anglian Water said the Greyfriars and Sheep Street sinkholes are not thought to have anything to do with the town's sewer network.
The cause of a third sinkhole in Lea Road, Abington, is not yet known.