What the colours mean
Radar renders reflectivity — how much energy droplets bounce back. Green is light, yellow moderate, red heavy or hail. It is an estimate of intensity, not an accumulation total.
Beam blockage
Radar beams travel in straight lines while the ground rises. Behind a ridge the beam overshoots the valley, so a snow squall on the far side of a divide can be invisible on the composite.
Using it in the field
Watch cell motion over two frames to judge direction and speed, then decide whether a front will push animals to timber before you commit to a long pack-out.