The water is so high sections of fencing bordering the road can't be seen.
The council said the both SH1 and SH72 would remain closed tonight.
Staff would have to wait for the floodwaters to recede so they can assess the damage and begin repair work.
It said it would focus on getting the bridge at Arundel open on a limited basis "as soon as possible".
It was recommending travellers go to Timaru on SH8 rather than Geraldine as there was better access to facilities.
NZTA have been inspecting the flood damage but access had been limited. Due to the flooding and road damage, the bridge is still unable to be assessed.
State Highway 6 on the South Island's West coast was closed from Hokitika down to Makarora, with several slips on the road. Settlements on the highway were cut off from each other because of the damage.
More than 350km of the highway was shut because of the slips and a bridge washout, New Zealand Transport Agency system manager Pete Connors told RNZ.
"The real problem we've got is between Fox Glacier and Franz Josef - on what we call the Fox Hills ... there's been some pretty substantial slips."
He didn't know how long it would take to repair the roads.
Spark said earlier today "almost all" of its impacted South Island broadband, mobile and landline services have been restored.
Power was also out from Fox Glacier to Paringa, and was likely to remain so for a couple of days.
Powerco have confirmed two lightning strikes in the New Plymouth suburbs of Strandon and Omata cut power to about 840 homes late this afternoon.
The first strike, in Strandon at 4.33pm, initially cut power to 710 homes. However, at 5.15pm only 498 homes were affected.
And 142 homes in the Omata suburb also lost power in the second strike, about 5 minutes later.
