Expanding Triangles signal the End of a Trend

In a Trend

An expanding triangle (XT) signals the end of a bull trend by taking out a higher low (HL) and vice versa on a bear.

Expanding triangles can occur as a couple of overlapping bars like on 2019/01/14 or as (easier to see) an expanding range with higher highs and lower lows like today.

Expanding triangles also often signal a start of a channel, like in a spike & channel trend.

In a Channel

there is a version of a XT in a channel called CXT – a channel expanding triangle, which is a pullback in a channel, that takes out a minor HL/LH
you can find a lot of examples on my charts, or just use CXT from the tag list