Hurricane Katrina will go down as the costliest storm in U.S. history, and one of the deadliest on record. It also triggered the largest-ever response to a domestic emergency by the National Guard.

Four hours after the storm passed, the Guard was in the water, on the streets and in the air saving lives. By Sept. 8, more than 51,000 Guard Soldiers and airmen were responding to the crisis -- more than three times the previous record for a natural disaster.

Even more remarkable was the scope of the Guard's response. Before it was over, the governors of every U.S. state and territory, as well as the District of Columbia, sent troops to the Gulf Coast. The willing cooperation of the nation's governors -- who command the Guard when it is not in federal service -- made it possible for the Guard to respond on this huge scale while simultaneously providing 79,000 troops for federal service in the war on terrorism.

Although the National Guard was lauded in congressional hearings as the most organized and well- prepared entity to respond to Hurricane Katrina, there were several lessons learned.

By far, the biggest problem the Guard faced in responding to Katrina was a lack of equipment -- radios, medical gear, trucks, helicopters and bulldozers. The list encompasses nearly every item in the Guard's inventory. Quite simply, deployments to Iraq and Afghanistan have taken a bad situation and made it worse.

Before Sept. 11, 2001, the Army National Guard had 76 percent of its required equipment. When Katrina struck, Guard units that were not mobilized for overseas service had less than 35 percent of their required equipment.

How did this happen? Units were stripped of their gear to ensure that units going overseas had everything they needed. Units returning from Iraq and Afghanistan often left their gear behind for follow-on forces, and what they kept was often worn out from hard use in a combat zone. Not enough money was budgeted to replace the damaged and left-behind equipment.

Of all the equipment shortages, the one that hurt most during Katrina was a lack of communications gear. With telephone lines and cell-phone towers down, troops had to rely on their tactical radios. Many Guard units were not issued SINCGARS radios, which are used nearly universally throughout the active Army, making communications with active-component troops difficult. Satellite communications capability was sparse. Talking to civilian emergency responders was also a challenge, because the civilian agencies use different kinds of radios.

The communications situation could have been much worse, but fortunately for the Guard, satellite communications capability had greatly expanded since 9/11. By the time Katrina struck, most state Guards had organized 22-person civil support teams designed to assist civil authorities in responding to potential weapons-of-mass-destruction incidents.

Each CST has a unified command suite -- a mobile communications van that can connect military and civilian radio networks and provide voice, data, Internet, and video uplinks that allow the commander at an incident site to contact anyone he or she needs to talk to, worldwide. More than 20 CSTs deployed their unified command suites to the Gulf Coast within the first month after Katrina struck.

The hurricane season of 2004, when Florida was thrashed by four hurricanes and a tropical storm, prompted the National Guard Bureau to begin fielding 13 satellite-communications systems for use in responding to domestic emergencies. These systems, known as the Interim Satellite Incident Site Communications Set, were exceptionally valuable, with many of the same communication capabilities as the CSTs possess.

Florida's ISISCS team was typical, deploying to Bay St. Louis, Miss., near where the eye of Katrina passed. The team supported three battalion-sized units that rotated through the area. When one unit requested assistance in boosting the range of their handheld radios, the ISISCS team was able to increase the range of the radios from two miles to 20 miles.

But the scale of the devastation caused by Katrina meant that those assets were not enough to get communications capability everywhere it was needed. In the aftermath, the Guard has recognized a need for more radio repeaters and satellite phones, to increase the range and reliability of communications, and more emphasis on communications gear that is compatible with civilian radios.

Largely as a result of communications gaps, it was difficult to get a common operating picture during the early phase of the crisis. As a result, different headquarters had conflicting information that slowed decision-making. Because disaster response is customarily handled at a state level, procedures for handling the response could cause confusion when transmitted to the national level.

“Lack of doctrinally correct reports, graphics and communications procedures caused duplications of effort, confusion and multiple requests for clarification of information,” according to the Guard Bureau's after-action review of Katrina. Recognizing this problem, the annual exercises the Guard holds to prepare for civil emergencies will focus more on applying a single standard for all states.

In the heart of the crisis, headquarters in the affected area were flooded with requests for information. In some cases, these buildings were flooded, too. The state headquarters and operations center for the Louisiana Guard was located at historic Jackson Barracks, on the edge of the lower 9th Ward in New Orleans. Inundated by more than 10 feet of water on the day the storm hit, Guard members had to save themselves and their families, relocate their headquarters to higher ground, and still try to coordinate their own forces as well as the rapidly arriving forces from other states and the federal government.

One lesson drawn from that experience was the need for mobile communications suites that can keep a headquarters that is on the move in touch with the rest of the world. Another lesson was the need to be able to expand command-and-control capability in a crisis.

The Guard's solution during Katrina was to mobilize two Army National Guard division headquarters, assigning the 35th Infantry Division from Kansas to support Louisiana and the 38th Inf. Div. from Indiana to support Mississippi. In each case, because Guard members are accustomed to working under the direct control of civil authorities, the out-of-state Guard troops integrated quickly into the host-state command structures. The solution worked well and will probably be implemented again in the future.

A significant lesson learned from Katrina had to do with percep-tions. Guard Soldiers are proud of the service they performed during and after Katrina, and see it as part of a long tradition of helping their neighbors through fires, floods and earthquakes.

Yet, with more than three times as many Guard troops actually on the ground in Louisiana and Mississippi as all of the active-duty Army, Navy, Air Force and Marine personnel combined, Guard members were dismayed to find that the national media consistently portrayed them as active-duty Soldiers under the command of the federal Joint Task Force-Katrina commander, as opposed to Guard members from all 54 states and U.S. territories, under the control of the governors of the affected states.

Despite discussions early on between the governors of the Gulf Coast states and President George W. Bush, the National Guard was never federalized. Instead, close coordination took place among the various states and JTF-Katrina. “We had unity of effort, not unity of command,” said LTG H. Steven Blum, chief of the National Guard Bureau.

By staying in a state status, Guard Soldiers were empowered to enforce civil laws, something federal troops -- including Guard members in federal service -- are prohibited from doing, except under the provisions of the insurrection laws.

Fortunately, both the Pentagon and Congress are paying attention to the most serious problem exposed by Katrina -- the lack of equipment. Beginning last fall, Congress authorized nearly $1.3 billion, specifically aimed at making up the shortfall in equipment for homeland defense that the Guard has identified. Among the first items expected to be purchased will be SINCGARS radios and other desperately needed communications gear. This is only a first step, however, in addressing a deficit of more than $7 billion in missing equipment.

Katrina was a learning experience for tens of thousands of Guard Soldiers who responded. “When you called out the Guard for Katrina, you called out all of America,” Blum said last November to a congressional committee that investigated the Katrina response. While it was a mission the Guard has performed for centuries, the scale was unprecedented. “There is not a single National Guard entity that did not make a contribution,” Blum said.

Given the regularity with which hurricanes strike the United States, and the same regularity with which the National Guard is called to respond, the lessons learned from Katrina are sure to have a long-lasting and positive impact for generations to come.