A strong upper level disturbance developed and moved into the inter-mountain west.  Ahead of this wave, a surface low pressure set up in the lee of the Rockies.  This surface low pressure system had a strong warm sector over southern and eastern Kansas where temperatures were in the upper 60s and low 70s with 50 to 60 degree dew point temperatures.  Also associated with this surface low was a very strong cold front.  As the upper wave moved eastward the surface cold front moved southeast.  This cold front was cold polar arctic air, but was very shallow, only extended a few thousand feet above ground.  What does this mean?  Well the mid and upper portions of the atmosphere over Nebraska, Kansas and Oklahoma were relatively warm, while the shallow cold air at the surface was plunging temperatures into the 20s and 30s.
The front moved through during the afternoon of April 9th, causing winds to instantly switch 180 degrees and temperatures to drop nearly 20 degrees in 10 to 15 minutes.  The cold air behind this front was so strong, the shallow surface front pushed into Oklahoma and Arkansas.
The combination of the shallow cold air and the warm mid and upper levels causes precipitation to fall as rain while surface temperatures are at or well below 32 degrees.  The rain that fell accumulated on elevated surfaces and froze.  Ice accumulations of a quarter of an inch up to a half of an inch were reported across Central and South Central Kansas.  The ground temperatures had been so warm that the non-elevated roadways were not as slick as elevated overpasses.
Reports of car accidents and tree damage as well as power outages were reported.

Ice Storm in SEDGWICK, KANSAS
From 10-APR-13 07:19:00 to 10-APR-13 14:43:00 (CST-6)
Reported by: Official NWS Observations

One quarter of an inch of ice was observed at the National Weather Service office.

Ice Storm in MARION, KANSAS
From 10-APR-13 05:49:00 to 10-APR-13 14:43:00 (CST-6)
Reported by: Emergency Manager

Ice accumulations up to one quarter inch were noted in the far southwestern section of the county.  Roads were very slick across the county.

Ice Storm in RENO, KANSAS
From 10-APR-13 02:05:00 to 10-APR-13 14:43:00 (CST-6)
Reported by: Law Enforcement

Up to one half an inch of ice accumulation was noted on area trees and power lines.  Several people were without power and the roads were very slick across the county.

Ice Storm in HARVEY, KANSAS
From 10-APR-13 05:49:00 to 10-APR-13 14:43:00 (CST-6)
Reported by: Law Enforcement

Ice up to one half inch in diameter was causing limbs and power lines to fall due to the extra weight.  The roads were also very slick and several accidents were reported.

Ice Storm in BUTLER, KANSAS
From 10-APR-13 08:30:00 to 10-APR-13 14:43:00 (CST-6)
Reported by: Trained Spotter

One quarter of an inch of ice was reported near Elbing in the far northwestern sections of the county.

Ice Storm in KINGMAN, KANSAS
From 10-APR-13 04:00:00 to 10-APR-13 14:43:00 (CST-6)
Reported by: Law Enforcement

Ice accumulations across the western half of the county were at one quarter of an inch.  The roads across the county were very slick and dangerous.

Ice Storm in HARPER, KANSAS
From 10-APR-13 03:22:00 to 10-APR-13 14:43:00 (CST-6)
Reported by: Law Enforcement

Ice accumulations of three tenths of an inch were reported on the trees and power lines.  The roads across the county were very slick and dangerous.

Ice Storm in ELLSWORTH, KANSAS
From 10-APR-13 05:43:00 to 10-APR-13 14:43:00 (CST-6)
Reported by: Law Enforcement

One quarter of inch of ice was measured.  This caused very slick conditions across the county.

Ice Storm in SALINE, KANSAS
From 10-APR-13 05:25:00 to 10-APR-13 14:43:00 (CST-6)
Reported by: Law Enforcement

Tree limbs and some power lines were downed due to the ice accumulation.  Several roads were also very slick due to the one quarter inch ice.

Ice Storm in RICE, KANSAS
From 10-APR-13 05:35:00 to 10-APR-13 14:43:00 (CST-6)
Reported by: Law Enforcement

One quarter of inch of ice caused tree limbs to be downed.  A few trees were also uprooted.

Ice Storm in MCPHERSON, KANSAS
From 10-APR-13 07:52:00 to 10-APR-13 14:43:00 (CST-6)
Reported by: Emergency Manager

One half an inch of ice was causing tree limbs to fall down.  Several power lines were also falling due to the weight of the ice.