As we drove through Eastern Washington we came close to a very unique erosional feature of truly epic proportions. The scablands earned their name for the scoured, wounded appearance of this landscape caused by cataclysmic flooding during the Pleistocene epoch (i.e., the ice ages). Lake Missoula was an ice age lake that held a volume of water half the size of Lake Michigan over the land area that is now Western Montana and Eastern Washington. At the western edge of this lake was a dam of ice that broke open several times over a period of a few thousand years. When the ice broke free, the water of Lake Missoula emptied into the Columbia River valley. Within only 2 days all the water drained out, the ice reformed, and the lake filled up again. Geologists have estimated that 2.7 million cubic meters of water flowed each second during this event! So for all you fourth graders let's do some math.
1) The first time this lake formed in the ice ages was about 15,000 years ago. How many hundreds is this?
2) When the lake was done emptying and reforming, it was a time in years-ago equal to 1,300 tens. How many years ago was this in standard form?
3) Using the two numbers from above (in standard form), how long did this period of flooding last? To solve for this answer subtract the smaller number (question #2) from the larger number (question #1).
4) Some geologists think that flooding over this time period (in question #3) happened 27 times. Rounding to the nearest tens place, how many times was this?
5) The fastest flow of water during each flood is hypothesized to have been 2,700,000 cubic meters each second. How many hundred thousands is this?
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