Rime Meteorology in the Green Mountains

Most rime events in the Green Mountains are of low intensity, with greatest intensities found in warmer, subfreezing air within 5 C of the dew point. Rime was usually most intense within deep low pressure systems, and was associated with 9- to 10-tenths cloud cover and light precipitation. Rime was rarely associated with high pressure. Most rime events occurred within cold and occluded fronts in southerly to westerly winds. Rime was most intense on the trailing side of cyclones as they moved eastward and poleward of northern Vermont. Nearly all rime deposits during the study period were from the west and northwest. Rosemount ice detector performance on Mt. Mansfield compared favorably to performance of an identical detector on Mt. Washington under similar icing intensities. Feather growth rates were not measured accurately by the Rosemount detector, however. Feathers on equipment exposed similarly to the Rosemount grew at nearly twice the rate indicated by the Rosemount detector. Rime accretion increases at an increasing rate with elevation in the Green Mountains. Rime events are infrequent and have low intensities below 800 m. Rime accretion near the ground surface also correlated with relief exposure, with promontories accumulating more rime than hollows.