Scientists say extensive cracking on the dome rising inside Mount St. Helens suggests there may be increased rockfall activity in coming weeks.

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The south end of the whaleback-shaped dome is falling apart, leading to more steam emissions from the crater.

Chopper 7 captured images of the new dome, which is now about 700 feet below the south crater rim.

The U.S. Geological Survey said analysis of recent aerial photos shows that by Feb. 1, the high point on the whaleback had reached an altitude of 7,650 feet.

MOUNT ST. HELENS Video: Time-Lapse Of Dome’s Growth Video: Time-Lapse Of Fin Growth Video: Thermal Imaging Of Rock Avalanche Slideshow: Hulking Rock Slab Grows In Volcano's Crater Slideshow: Images From 3-8-05 Ash Plume Slideshow: Infrared Shots Of Activity At Mount St. Helens Slideshow: Dome In Mount St. Helens Crumbling Slideshow: Glowing Lava Oozes From Crater Slideshow: Large Plume Drifting North-Northeast Slideshow: Steam Eruption On 10-4 Slideshow: User Submitted Mount St. Helens Images Slideshow: Steam Vent Forms After Eruption Images: Mount St. Helens Gets Steamed Slideshow: Steam Shoots From Crater Webcam: Mount St. Helens VolcanoCam Complete Coverage Of Mount St. Helens

That's nearly 1,400 feet above the 1980 crater floor, and 500 feet above the top of the old lava dome.