FEMA

FEMA ( Federal Emergency Management Agency ) has a network of shortwave stations between their regional offices: The day primary frequency is 10.493 MHz USB and night primary frequency is 5.212 MHz USB.

Net is called almost daily on 10.493 MHz at 1600 z ( 1100 EST or 1200 EDT ).

Each Monday, Thursday and Friday by primary net control station in Philadelphia, PA.
Also 1st Tuesday in January, April, July, October by primary station in Philadelphia, PA.
Also 1st Tuesday in February, May, August, November by 2nd alternate in Denton, TX. 
Also 1st Tuesday in March, June, September, December by 3rd alternate in Thomasville GA.
Then 2nd Tuesday in March, June, September, December by 4th alternate in Battle Creek, MI. 
Finally, every Wednesday an open drill between all regional stations. During any disaster or emergency, the affected state is in authority.

FEMA HQ Washington DC
Region #1 Boston: CT MA ME NH RI VT 
Region #2 New York City: NJ NY PR VI 
Region #3 Philadelphia: DC DE MD PA VA WV 
Region #4 Atlanta: AL FL GA KY MS NC SC TN 
Region #5 Chicago: IL IN MI MN OH WI 
Region #6 Denton: AR LA NM OK TX 
Region #7 Kansas City: IA KS MO NE 
Region #8 Denver: CO MT ND SD UT WY 
Region #9 Oakland: AZ CA GU HI NV 
Region #10 Seattle: AK ID OR WA 

2.321 ( Foxtrot 06 ) Regions 8,9,10
2.361 ( Foxtrot 07 ) Regions 6,8,9
2.375 ( Foxtrot 08 ) Region 4
2.446 ( Foxtrot 09 ) Regions 1,3,5,9,10
2.659 ( Foxtrot 10 ) Regions 3,4,7,8,10
3.342 ( Foxtrot 11 ) Regions 4,5,6,7,8
3.380 ( Foxtrot 12 ) Regions 5,6,8,9,10
3.390 ( Foxtrot 13 ) Regions 5,6,7,8
4.603 Region 4
5.212 ( Foxtrot 15 ) All regions, night primary frequency
5.403 ( Foxtrot 16 ) Regions 9,10
5.822 ( Foxtrot 17 ) Regions 1,2
5.962 ( Foxtrot 18 ) Regions 1,2,3,4,5,6,8,9,10
6.050 ( Foxtrot 19 ) Regions 3,5,8,10
6.107 ( Foxtrot 20 ) Regions 3,4,6,7,8,10
6.109 ( Foxtrot 21 ) All regions
6.152 ( Foxtrot 22 ) Regions 3,4,5,6,7,8,9,10
6.177 ( Foxtrot 23 ) Regions 6,8,10
6.180 ( Foxtrot 24 )
6.809 Regions 9,10
7.349 ( Foxtrot 25 ) Regions 1,4,5,6,8,9,10 Point-to-point primary frequency
7.428 Region 4
9.463 ( Foxtrot 26 ) Regions 9,10
10.493 ( Foxtrot 28 ) All Regions, day primary frequency, 
10.589 ( Foxtrot 29 ) Regions 8,9,10
10.793 Region 9
10.407 ( Foxtrot 30 ) Regions 1,4,6,8
11.802 ( Foxtrot 31 ) Regions 3,6,8,9,10
11.958 ( Foxtrot 32 ) Regions 5,7,8,9
12.010 ( Foxtrot 33 ) Regions 9,10
12.217 ( Foxtrot 34 ) Regions 5,6,8,9,10
14.451 ( Foxtrot 35 ) All regions
14.777 ( Foxtrot 36 ) All regions
14.837 ( Foxtrot 37 ) All regions
14.886 ( Foxtrot 38 ) All regions
14.900 ( Foxtrot 39 ) All regions
14.909 ( Foxtrot 40 ) All regions
16.202 ( Foxtrot 41 ) Regions 9,10
16.431 ( Foxtrot 42 ) Regions 9,10
17.520 ( Foxtrot 43 ) Regions 9,10
17.650 ( Foxtrot 44 ) Regions 5,8,9,10
18.745 ( Foxtrot 45 ) Regions 9,10
19.758 ( Foxtrot 46 ) Regions 9,10 
19.970 ( Foxtrot 47 ) Regions 9,10
20.028 ( Foxtrot 48 ) All regions 
20.405 Philadelphia, PA ( Primary Net Control ) to Washington DC
21.919 Denver, CO ( 1st Alternate ) to Mt. Weather VA
27.850 Philadelphia, PA ( Primary Net Control ) to Washington DC

FEMA information and frequencies obtained here.
Additional information about FEMA and SHARES can be found here

AMERICAN NATIONAL RED CROSS operates shortwave base stations and mobile units for long-distance emergency communications. The listed locations and frequencies, from the FCC database.
Washington DC, Austin TX, Kansas City MO and Berryville VA. 
2.326 2.463 2.801 3.170 3.201 5.135 5.140 6.858 7.480 7.549 7.697 7.932 7.935 
Gretna LA has only one frequency listed: 3.201 MHz, USB only.

SHARES 

Shared Resources High Frequency Radio Program (SHARES) ( SHAred RESources ) is a network of over 1000 stations representing 93 federal, state and industry sharing radio resources throughout the United States and in 26 countries and U.S. possessions to voluntarily pass emergency messages when normal communications are destroyed or unavailable.  SHARES uses common radio operating and message formatting procedures and more than 250 designated frequencies. They have standardized message formats and procedures, so any agency can transmit emergency messages for other agencies. Each agency maintains their own ( unpublished ) frequencies. Drills and weekly nets are called on Wednesday 1600 - 1800 z ( 1100 - 1300 EST or 1200 - 1400 EDT ). Large scale drills are conducted in April, August and December. Participation in SHARES is open to all Federal departments and agencies and their designated affiliates on a voluntary basis.

4.490 5.236 5.711 5.901 6.800 7.632 9.064 9.106 10.5865 11.108
11.217 13.242 14.3965 14.455 14.3965 15.094 17.487 20.107 26.812

Information about SHARES found here.