There is a bug in the Cairo 2D Vector Graphics library in the version of Iceweasel in Debian Jessie at the moment (31.2, based on Firefox ESR 31.2) which results in Street View freezing.
A solution might be to install the latest version of Iceweasel from the Debian Mozilla team, as the bug is apparently fixed in Firefox 33. (Haven't tried this myself.)
A work around is to use Chrome or Epiphany/Web, which are not affected.
Update: or use Classic Maps, which uses Flash. (Debian Forum).