Storm surge question. Let's say someone's house is 20 feet above sea level in the storm area, and

[raccoon]

the storm surge is 15 feet. Does that mean the house and its denizens are safe from the water?

[L. Coyote]

1. Not necessarily.

As water body width decreases, the funnel effect can raise the waves of water moving inland. How high you are above the nearest water channel matters too.

[LuckyCharms]

2. I'm pretty sure that storm surge represents

the water level above normally dry ground, not above sea level.

If this is the case, the house would not necessarily be safe.

[Igel]

9. It's the increase in sea level above what it would be without the storm.

Sea level averages out tides.

Storm surge is above whatever the level is with the tide.

[Hoyt]

3. If my house were on stilts, I would not like 15 feet of swirling sea water below.

[TexasBushwhacker]

4. Exactly

You may be dry and safe, but you probably won't have power or a way to escape safely, even with a raft.

The one saving grace for Irma is that it's continuing to move, rather than stalling out and dumping feet of rain in one place like Harvey.

[eppur_se_muova]

5. Don't forget to consider high tide. That may add a few feet. nt

[csziggy]

6. And waves, which can be feet taller than the water level. nt

[meadowlander]

7. And backups to stormwater drainage systems from the rain.

[BigmanPigman]

8. Tides and waves are factors to consider as well as the foundation and materials used

in your building foundation.

[Igel]

10. Lots of people have said "no, not necessarily."

One more is simple momentum: If you go to the beach and a "surge" comes on shore in the form of a way, not only it it be funneled, not only might it have ripples, but its forward momentum will take it farther up the shore than you'd suspect, and it might stay there longer because it's pushed from behind.