NOAA lidars at wavelengths of 0.574, 0.694, and 10.591 &mgr;m have observed ejecta from the eruption of Mt. Pinatubo both in the troposphere and stratosphere over Boulder, Colorado, since July 27, 1991. Multilayered clouds have been highly variable on time scales of minutes to days. Measurements at multiple wavelengths provide valuable information on size distribution and the wavelength dependence of backscatter and optical depth. ¿American Geophysical Union 1992