That storm may last two days," yelled Frank to me.
"We've had some bad ones lately.

Give your horse free rein, and cover your face." A roar, resembling an approaching storm at sea, came on puffs of wind, as the horses got into their stride.

Long streaks of dust whipped up in different places; the silver-white grass bent to the ground; round bunches of sage went rolling before us.

The puffs grew longer, steadier, harder.

Then a shrieking blast howled on our trail, seeming to swoop down on us with a yellow, blinding pall.