If this happens, shut your mower off before you reach under the deck to remove the clumped grass. Just disengaging the blade is not enough; mowers have been known to re-engage while someone has his hand under it.
Slipping on the wet grass can be very dangerous. This is most common on slopes, especially with riding mowers. Besides soil compaction, sliding across the lawn can rip grass plants out of the ground and cause ruts. Most important, slipping can flip the mower over, which is hazardous. Even using a walk-behind mower on a slope can be dangerous.
For maximum safety, riding mowers should be driven up and down the hill so you don’t flip over sideways.
Walk-behind mowers should be used going sideways on the hill; that way, if you do slip, the mower won’t roll over you. Wear work boots with a good grip to them to minimize slipping.
You may be noticing that the turf grass in low-lying areas, poorly drained soils and where downspouts discharge is beginning to turn yellow or brown. This is mostly due to the saturated soil, which has pushed all of the oxygen out of the soil. The grass plants are basically drowning. Disease spreads quickly when the grass is wet. Fungi and bacteria love nothing more than water for moving around.
Redirect downspouts if they are flowing onto highly visible lawn areas, but make sure they don’t discharge into shrub beds.
The best advice I can give for lawn care right now is to set your mower to the highest blade setting. Try to cut frequently, removing no more than one-third of the grass height with any one mowing. This will reduce clumping and stress on the lawn.
Remove the mower bag for now; trying to send wet grass through the narrow chute opening will cause frequent clogs. You can rake up the cut grass and place it in the garden or wait for it to dry and run your mower over it again.
If you plan on fertilizing within the next several weeks, be absolutely sure to use slow-release forms of nitrogen to prevent quick bursts of growth that will increase the need for mowing.