When a volcano erupts in a huge pyroclastic eruption, it can form lots of different types of volcanic deposits. 1) what are pyroclastic flows (nuees ardennes)? 2) how fast do they travel? 3) how hot are they, typically? 4) what are the deposits of these pyroclastic flow eruptions called?

As tephra and pumice

Explanation:

A pyroclastic eruption is generally in the form of a cloud of fast-moving currents of violent gas, and volcanic matter collectively known as tephra that moves at the speed of 100 kilometers per hour and is capable of reaching at 700 km and can reach up to 1000 degrees C. Commonly result from violent eruptions of lava and there speeds depends on the current volcanic output rates and gradient of the slope. The cause is a fountain and gravitational collapse. Upon interaction with water forms streams of hot ashes with varying densities,  and flows can eventually built deltas with mud and may flow down the slope in the form a lahar. The flow deposits may e massive and graded basal zones. Discontinuous large segments are a fine-grained, orientation of elongate or platy clasts.

Water flows along the east coast and across the western tropical pacific towards south america, while they both are directed towards that way,  el niño does not directly affect the southern flow of water along the coast.