Countermeasures for ice covered waters*

Abstract: This chapter describes the state of knowledge regarding the most applicable countermeasures to deal with oil on, in or among ice. Countermeasures are discussed in the context of seasonal variations in ice conditions and observations of oil fate and behaviour in a variety of different situations. The behaviour of oil spilled in ice covered waters is governed largely by the ice concentration in the case of broken ice, and the processes of encapsulation and subsequent migration in the case of solid (fast) (ice). Each season presents different drawbacks and advantages for spill response. During freeze-up and break-up, drifting ice and limited site access tend to restrict the possible response options and significantly reduce recovery effectiveness. Mid-winter, although associated with long periods of darkness and cold temperatures, provides a stable ice cover that not only naturally contains the oil nearshore within a relatively small area but also provides a safe working platform for oil recovery and transport. For the case of spills under or on fast ice, there are a range of effective counter-measures options which can result in very high recovery effectiveness. Countermeasures to deal with spills in moving pack ice are much more limited and likely to result in highly variable recovery values depending on a variety of natural conditions and logistics constraints