It's rather simple, actually: As you depart and start an en route climb
, take time to check conditions for the next phase--and then decide to either continue and fly it, or make a new decision.
Another example is the apparently competent pilot in a cross-country airplane asking ATC's permission for en route climb
or descent while receiving flight following.
At 1439 Pacific time, the scheduled American Eagle flight encountered icing conditions during its en route climb
at about 11,500 feet msl and departed controlled flight.