What is the difference between a pyroclastic flow and nuee ardente?

Question

Some sites say these are the same others different but do not say how they are different. Anyone know?

Answer 1

According to the Encyclopedia Britannica, they are the same, except that one is English (via Latin) and one is French.
"One feared phenomenon accompanying some explosive eruptions is the nuée ardente, or pyroclastic flow, a fluidized mixture of hot gas and incandescent particles that sweeps down a volcano's flanks, incinerating everything in its path."

However, there is an alternative interpretation:
"A glowing cloud or Nuée Ardente is a gas-generated eruptive phenomenon consisting of two parts.
1) glowing avalanche (lower denser part)
2) lighter fraction of volcanic gases, ash, and dust which cauliflowers upwards.
A nuée ardente consists of two parts where a pyroclastic flow only relates to the lower glowing avalanche."

That view is supported by San Diego State University:
"A pyroclastic flow is a fluidized mixture of solid to semi-solid fragments and hot, expanding gases that flows down the flank of a volcanic edifice. These awesome features are heavier-than-air emulsions that move much like a snow avalanche, except that they are fiercely hot, contain toxic gases, and move at phenomenal, hurricane-force speeds, often over 100 km/hour.
Although the term nuée ardente is now applied to all pyroclastic flows generated by dome collapse, it is somewhat of a misnomer to describe these features as a "glowing cloud." A more precise term would be glowing avalanche. The bulk of these hot block-and-ash flows hug the ground surface, but are disguised by an overlying cloud of fine ash particles... Nuée ardentes, therefore, are composed of two related parts: a pyroclastic avalanche largely hidden from view by an overlying ash cloud..."

Answer 2

Nuee Ardente