With the first taste of ‘real’ winter being forecast for the next few days, Norfolk County Council’s salt stocks for treating roads are a healthy 15,000 tonnes – enough for up to 50 standard gritting runs.
So far this winter a see-saw pattern of often windy weather has kept the number of gritting runs down, with only 20 by mid January. Last winter (2013-14) was even milder – but forecasters now expect cold weather to set in over the weekend and through much of next week, with a risk of sleet and snow showers.
Nick Tupper, Norfolk County Council’s Highways Maintenance Manager, said drivers could well find themselves facing road conditions they had not encountered for nearly two years. He urged them to allow more time and take extra care.
“Even roads on the treated network can become icy. We try to get out early and have the roads salted before they can freeze, but weather conditions can make the timing of gritting runs very difficult. It’s pointless to put down salt during heavy rain, but roads can freeze quickly when skies clear. If gritters go out as soon as the rain stops, it will take up to three hours to complete the run.
“There’s always the chance that run-off from fields will freeze, even on treated roads, and of course many minor roads – over 60% of the network in fact – are not on the priority gritting routes. During cold snaps there’s always the chance that a shady corner will stay icy, and wet roads can quickly turn to black ice in the evening.
“It’s also a myth that snow won’t settle on treated roads. Heavy snow falling on a salted road causes a rapid drop in road surface temperature. Salt then becomes less effective at melting the snow and ice, so even treated roads can become snow covered. In time treated roads will clear down to the asphalt again, but it often takes the action of traffic – especially heavy vehicles – to speed up the process.”
The gritters have already been out tonight on all county gritting routes (you can find out which roads are on our gritting routes here) and will go out again at 4am and tomorrow afternoon.
Norfolk County Council gritting key facts 2014/15
• Total length of county highway network: 5,965
• Length of priority (1&2) gritting routes: 2,083 (37%)
• Number of gritting routes: 48
• Time taken for full treatment: 3 hours
• Average cost per action: £40,000 (including fixed costs).
• The Highways Agency treats the A11, A12, A47 trunk roads (143 miles)
In prolonged severe wintry weather, priority 3 roads are treated as resources allow. In snow, the council can call upon 90 farmers to snow plough local roads.
In addition there are over 1,800 grit bins around the county that have been filled by the County Council.
Norfolk County Council has a long-term contract with Salt Union to supply salt and maintain supplies above a minimum level.
At the start of the season the stocks in Norfolk are 17,180 tonnes, held in seven salt domes and one 5,000 tonne strategic reserve (Swaffham). This is sufficient for over 50 actions (at 15 grammes per square metre). There is a further 3,000 reserve held at Ellesmere Port, Lancs.
Salt Union are under contract to maintain the in-county stocks above a minimum level of 7,665 tonnes – about 24 actions.
The 2013/14 winter was exceptionally mild but the wettest for over 100 years. There were 65 gritting actions, using 15,679 tonnes of salt. The total cost (including fixed costs) was £3.5m. The average cost per action was almost £54,000.
The severe 2012/13 winter
In contrast, 2012/13 was a record winter for gritting actions. There were 159 altogether, using over 41,000 tonnes of salt between 27 October and 4 April.