The scale used to measure the intensity of ice storms is called the Sperry–Piltz Ice Accumulation Index, based on the expected footprint of an ice storm, the expected ice accumulation as a result of a storm, and the expected damage a storm inflicts on human-built structures.
Meteorologists use Dual Polarization Radar, and the Q2 a mix of sensors and algorithms to predict precipitation.
Yes ice storms can be predicted by weather agencies, and it depends how fast it is detected and how severe it is.