Chris said:

This year is my first with a patch of corn. I have a raised bed (4 x
16) devoted to corn and probably planted the corn too close together,
but, what the heck. The corn started to tassle and I had small
silkies coming from the stalk - life was good. Monday night, though,
we were hit by a massive severe thunderstorm which flattened about
seven-eighths of my crop. What left standing just depresses me. Now,
my neighbors with acre-big crops of corn don't seem to have suffered
much at all.

Their good luck, partly. Straight line winds from thunderstorms have been
known to lay over groups of TREES. Field corn can suffer blow-downs.

I also suspect the large fields are most vulnerable to lesser winds at the edges.
Compared to the large field, your small patch is all edge.

What do I do now? So far, I've done nothing and the stalks are still
green and don't seem too dead.

Stand it all back up. Bring in garden soil or (even better) some good compost
and plop it down at the bottom of the corn stalk. Locate the mound of compost
where it will do the most good to prop up the plant. This might not be enough
for tall corn. In which case, drive some stakes along the end of each row and
run some twine along the row, looping the twine around the stalks to prop them
up and tying it of to the stakes at each end. Or, with block plantings, run a
grid of twine through the plot to prop them up. And then do the compost at
the base of the stalk thing.

And finally, how do I prevent this in the future?

You are never going to prevent it completely, but to minimize the chances,
hill up the corn with soil brought in from another bed or with compost before
it gets more than thigh high. Make sure your soil is not short of potassium.
(I give my corn extra K to help ensure strong roots and stems.)

Keep on hand materials to prop it up.

I have had no blow-downs for a couple of years, then suffered one this year.
We have had some unusually strong, fast moving storms this summer.

--
Pat in Plymouth MI

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)