Frost load is an important loading condition to consider for the design of buried pipes. Though frost loads can be much greater than earth loads, it is not presently possible to estimate frost loads except using heuristic arguments. This paper describes the development of simplified methods to estimate frost load. Important variables are identified that can explain how the effects of frost loading can be mitigated. Sensitivity analyses are presented to highlight the importance of the different variables involved in the simplified methods. Frost loads measured in a field case study are compared with calculated frost loads in trenches with clay and sand backfills. Key words: frost load, frost depth, buried pipe, trench backfills, trench width.