Lack of adequate soil moisture is often a major cause of winter damage. Dry soil coupled with strong winter winds can cause havoc on a plant. All plants, but especially narrowleaf and broadleaf evergreens, use water during winter. When little or no soil moisture is present, plants can become desiccated and it is more likely root damage will also occur.

When dry cold fronts are predicted, water the landscape at least 24 hours in advance of the front. Apply about ½ inch of water at the time of watering. A sunny day on moist soil helps warm the soil and root area thus reducing the amount of time the roots will be exposed to cold temperatures.

Read more at https://agriculture.okstate.edu/departments-programs/hla/research-extension/horticulture-tips/december.html