Calving tidal glaciers

A recent video from a calving tidal glacier in Greenland...

For the past 15 years, I have used the rule of thumb: 1x3 (three times the height away), and more in unstable weather pressure. This rule is also used by expedition boats at Svalbard and has served well so far.

I'll leave you to judge if this is enough...
http://sermitsiaq.ag/node/131604