Hello. I'mM.Jackson. Iama glaciologist.Istudyglaciersaroundtheworld. Aglacierisamovingriverofice. ItflowsoverEarth'ssurface. Whenaglacierflowsintowater,theicecancalve, orbreak off.

Aseracisaridgeoficeonthesurfaceofaglacier.Thesestickuplikesharkfins.Theycanbefuntoclimb.Acrevasseisacrackinaglacier.Ifellinone,once.Luckily,myteamfishedmeoutofthedeep,icy crack.