The valley, on the Far Eastern Kamchatka Peninsula famed for its volcanoes, contains about 90 geysers and an array of thermal pools.
Sunday's landslide buried about two-thirds of the valley, the RIA-Novosti news agency cited local officials as saying. Tourists and park personnel were evacuated, but no injuries were reported.
The extent of the damage to the valley's geysers was not immediately known, but experts feared many of them were obliterated.
"The consequences of such a natural catastrophe are irreversible," said Oleg Mitvol, the deputy head of Russia's environmental watchdog agency Rosprirodnadzor.
Putin's official spokesman Dmitry Peskov commented on remarks in the US media about failures in launching nuclear-capable missiles in Russia
The Buk system that shot down MH17 belonged to the 53rd SAM missile brigade of the Russian Ministry of Defense, investigators say after looking at a few pictures on the net
It has long been understood that the West has been trying to subject Russian borders to total control. We have not seen such activity even during the Cold War