Based on this information not much (< 1 m^3/s) is flowing through the debris.

In a new video the water level is higher (1542.5 m) than before (yesterday). The difference in volume roughly comes down to an addition of about 4 m^3/s assuming 24 hours difference with the previous video level (1538 m). This is also about what the river discharge was before the event.

All these events register nicely on the map. This is the biggest rockfall event and the seismic signal geolocates just at the base of the ridge. Also the geological situation and the permafrost question is illustrated (darker violet/blue means permafrost is more likely than yellow).

A long series of similar rockfall/rockslide events in Switzerland now has another BIG dot in the upper right hand corner:

Helicopter view published by Pomona Media (🔗 below) shows the lake building up by the end of the day. 5 m3/s is a lot of water.
youtu.be/R0YlCNDW2l4?...