[Ditter]

A tsunami in the Gulf of Mexico?

[t-1000]

"A tsunami in the Gulf of Mexico?"

Yes.
There is evidence that a giant asteroid crash just of the coast of the Yucatan peninsula.
That asteroid would have cause a tsunami with erroneous waves. Possibly hundreds of feet high.

[TexasCowboy]

The difference in the Gulf is that as the tsunami came from water thousands of feet deep and crawled up on the Continental Shelf, it's height would grow dramatically.

You'd see that sucker for a long time before it hit!

[DBrow]

The Chixsulub(sp?) impact set up a tsunami that left debris tens of miles inland in what's now Texas and Louisiana.

The Chesapeake impact likewise sent stuff way inland.

Any big enough meteor will make a powerful wave if it hits water.

The Barringer impactor was only 100 yards in diameter, and left a hole a mile wide. Had it hit water it would have made a huge wave also.

But impacts are rarer than big earthquakes by a few orders of magnitude.