The beaches in Florida's Miami-Dade and Broward counties, among the most popular, have run out of sand.
The U.S. Army Corps of Engineers is holding meetings this week to figure out where they can get more sand from, according to the Associated Press. They have to work fast to protect the shoreline from erosion during future hurricanes.
Beaches are formed by the erosion of offshore rocks and promontories. The fine size crystals of quartz and other material are carried onshore by waves and deposited on the beach.
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Even the material offshore has to come from somewhere, and that source is inland erosion. Rivers carry the sediments and deposit it off the coast.
The problem is we've dammed up rivers and built up harbors, so there's less sediment replenishing the material offshore these days. Humans are now the greatest shapers of landscapes, moving much more Earth than wind or water. At the same time, we have a proclivity for storm-prone coastlines that are increasingly under threat from erosion and climate change.