Author Question: The outflow at the top of a hurricane prolongs the storm's lifespan because: A) it helps to bring ... (Read 70 times)

cabate · **on:** Jul 14, 2018

The outflow at the top of a hurricane prolongs the storm's lifespan because:

A) it helps to bring in cold air to strengthen the hurricane's eye.
B) it provides an outlet for excess moisture that might otherwise rain out the storm.
C) it prevents surface convergence from filling in the low-pressure center of the storm.
D) it causes winds to converge at the top of the storm.

Question 2

Describe pyroclastic flows and explain why they are capable of traveling great distances.

What will be an ideal response?

karlss · **Reply #1 on:** Jul 14, 2018

Answer to Question 1

C

Answer to Question 2

Pyroclastic flows consist of hot gases infused with incandescent ash and larger lava fragments. Also referred to as nue ardentes, these fiery flows are capable of racing down steep volcanic slopes at speeds that can exceed 100 kilometers per hour. Pyroclastic flows are propelled by the force of gravity and tend to move in a manner similar to snow avalanches. They are mobilized by expanding volcanic gases released from the lava fragments and by the expansion of heated air that is overtaken and trapped in the moving front. These gases reduce friction between ash and pumice fragments, which gravity propels downslope in a nearly frictionless environment. This accounts for the reason some pyroclastic flow deposits are found many miles from their source.