yellow brown is probably from weeds, should be clear black ice this time of year. We were cutting 6 inches of solid black ice at my place on sunday. with the rain and this cold weather we will be cutting 10" to a ft this weekend. Ice that is not as safe would be the milky white ice, also if the ice looks blue/grey, kinda like a coon that is almost prime but not, stay off that stuff, usually see that near the end of the season.