A/C freezing up

[sawdust123]

I have a wierd and very intermittent problem that just started happening this year. My A/C will occasionally freeze up. At least I think that is what is happening. Here is the scenario.

I'll be driving with my A/C on low and when I turn up the blower, I can hear the fan speed pick up but the airflow remains at a trickle. If I shut the A/C down for a few minutes, everything goes back to normal.

My only hypothesis for this problem is that there is ice forming in the evaporator due to humidity in the outside air and the low fan setting. This blocks the airflow. When I shut off the A/C for a while, the ice melts and the flow is restored.

I feel good about my hypothesis except for one issue. This problem never raised itself during my first two years of ownership. What could have changed? Could there be an air leak, clogged drain whole or some other persnickety culprit like a leaf inside the evaporator?