The lake is about 30 feet deep in the middle and is an average size around. How long should l wait until l smooth it over before l can skate? Also, how thick should the ice be?

Actually thats not such a good idea
becuase the ice is suppose to be very shallow its basically not suppose to be more than a foot deep!
But if you really want to skate there wait until it is VERY VERY thick

It is not advisable or safe to skate on such a lake without it being maintained for that purpose and checked regularly for thickness. l personally would NEVER skate on ice that was less than 12'' thick. Another thing to be aware of is that ice can be frozen different thicknesses in different spots across the lake.

Do not do it. the ice will not be consistent, and if you go through the ice you are very unlikely to get out again.

When you see a guy drive a pickup truck on it to go ice fishing. Ice fishermen use an auger to drill a hole to test how thick the ice is. If somebody has not done that and said the ice is 1-2ft thick forget it. Could not pay me. flood your yard . same effect, less likely to die.

when its frozen