HOW TO: Hurricane Surge and Flood Projection With Google Earth

Since Hurricane Harvey last year I’ve been putting out virtual mock-ups of the flood damage in areas that will be affected in the hopes of getting people to visualize and therefore realize the dangers they are facing. Once I started doing this people started asking me to do their own specific locations, so I’ve decided to release instructions that will allow anybody with Google Earth (it’s free) to do their own mock-up visualizations like the one below, this is just a screenshot, but inside Google Earth you can ‘walk around and explore the damage:

Instructions:

1). Download Google Earth Pro.

2). Turn on 3D buildings and navigate to your area of interest.

3). Click the Temporary Places folder in the Places column (it will get a background) then right click > Add > Folder. Add a name in the dialogue box and tick the ‘Show contents as options’ box.

4). Right click the folder you’ve just created > Add > Polygon. Move the dialogue screen that opened out of the way (I move it to the bottom of the screen) and click the 4 corners of a square. Make it less than 10 miles across otherwise weird things happen to the layer because of the curvature of the earth.

5). Under the ‘Style, Color’ tab in properties, then using the controls titled ‘Area’ select a blue, then select an opacity of 70%. Now under the Altitude tab choose an altitude of whatever the storm surge is, in this case it’s 13ft or 4 meters and then select ‘Absolute’ in the pull down menu. This will raise your water 4m above the ground. Click okay:

And that’s it! Now you can zoom in and navigate around your own local area and clearly see how high the water will get on a street by street basis, and it takes into account the buildings and topography of the land.

Sidenotes:

3D Buildings: It’s a lot of fun to turn on the 3D buildings layer whilst you have sheets visible in the layers column, as in the screen shot the layers will show how deep buildings would be under.

Absolute Heights: Don’t select an area more than 10 miles square if you do the polygon behaves oddly, it doesn’t meet the land at the height you would expect. I’m not sure why this is but it may do with the curvature of the earth (in the middle of a big square the earth will protrude through a level sheet even though there is no topography).

Surface Flicker: If you zoom into the layers from a distance you may see line of where land meets sheet flicker and change. This is because Google Earth creates the view of the earth you see by taking the satellite images and draping them over a set of ‘posts’ it builds rather like a marquee tent. If you view the ground from a higher altitude Google Earth uses fewer posts so the surface changes as you zoom in and out.

Just for shits n giggles – Here’s New York with a disaster movie quality 80 meter storm surge: