Possible Clues:

• Woman gets to lie down? That's the height of ambition!
• Beginning to slip off harshest mountain
• On record, estimated height
• Mountain most uncompromising, peak unseen
• First Lady and others come to mountain
• Peak volume in middle of week then quiet
• First lady to settle on a mountain
• It's often climbed in severe storm
• World's highest mountain above sea level
• Mountain, most demanding without foremost of Sherpas