Ice that has thawed slowly and appears milky or opaque is known as?

• A. Clear ice
• B. Rotten ice
• C. Drift ice
• D. Pack ice

Answer: (B)

The situation being tested is how ice appearance relates to its strength and how thawing cycles affect reliability. Milky or opaque ice that has formed after a slow thaw is rotten ice. When ice thaws gradually, meltwater can percolate and refreeze, trapping air and impurities between ice crystals. This creates a cloudy, milky look and, more importantly, a weak, porous structure. Because the crystals don’t bond well, rotten ice can fail under load even if it looks thick enough, making it dangerous to step on or rely on for support.

In rescue work, you treat milky, opaque ice as unsafe and avoid assuming it can bear weight. Use probing to check actual conditions, employ safety ropes or lines, and prefer crossing on clearly solid, transparent ice if possible. Clear ice is strong and appears transparent, while drifting ice and pack ice describe surface conditions and motion rather than the ice’s internal quality.