https://airtribune.com/2017-quest-air-cross-country/blog__day_33

This was a smooth thermal (recorded at one second intervals on the XCTracer):

We entered it at about 5,700' and left at 7,000'. The average climb rate was 455
fpm. The climb rate distribution was:

We had just left a thermal that was too rough.

This is the last thermal from Wednesday's flight as Niki and I climb wing tip to
wing tip almost three thousand feet from just below three thousand feet. The
climb rate is about 250 fpm. It is a rough thermal with many variations in the
climb rate:

This is the climb rate distribution:

You'll notice lots of time spent at less than 150 fpm, often zero or negative
100, 200 or 300 fpm.

These climbs, the first one at 14:52 and the second at 16:14 were less than two
kilometers apart.

The much stronger thermal was much smoother.