OPERATION COLDSTREAM
A Situation Develops at the End of the War in Europe

Source: Occupation Forces in Europe Series - The First Year of the Occupation. Published by the European Command, 1947.
Southern Austria and around Trieste (p. 9, First Year)
To assist the 15th Army Group in Italy and Austria, the 12th Army Group was ordered on 22 May to prepare to move two corps through the Alps into Carinthia to relieve the British. The follwoing day these corps began the movement south, but after reconnaissance and a request from the British this movement was delayed until the congested area could be cleared. Meanwhile, the situation improved and the forces held on alert for movement to Carinthia were reduced to one corps on 14 June and were entirely relieved twelve days later.

Source: Mission Accomplished, Third United States Army Occupation of Germany. Published by HQ Third Army, March 1947.
Information was later forthcoming from SHAEF that the situation to the South, which had been discussed in the conference of 18 May, was deteriorating. Accordingly, Third Army was instructed to undertake a series of strategic moves whose purpose was to insure complete secutiry within this area.

A question was raised as to the opposition likely to be received from these moves by other forces, and the answer was received from the Army Group Commander that having been given a route and destination, Third Army was to proceed to accomplish the mission. In the event that an obstruction of some nature was placed in its path, full authority was given to use any and all means to overcome that obstacle. Thereupon the movement began and proceeded as planned although mobility was hampared by lack of suitable roads and the fact that available roads were icebound and covered with snow.

Instructions were received on 24 May to the effect that the forces committed to the south by Third Army in accordance to previous instructions were to remain in STATUS QUO. . . no additional units to be sent and none to be recalled until further orders were given. In complying with this directive the situation was static during the remainder of the month.

Source: Third US Army and Eastern Military District - Report of Operations, May - Sep 1945
As for the potential trouble spot to the south, the rapid and powerful movement of troops of the Third Army completed a juncture with the 15th Army Group and clarified the confused picture. This decisive move undoubtably served the very important purpose of insuring to the world that the United Nations were prepared to take any and all steps necessary to prevent any unilateral action by a power, or powers, bent on the exploitation of confused situations by moves of "Force Mateure".

In a letter of instruction (18 May 1945) Third Army was specifically instructed to gain contact with 15th Army Group troops in the south in the vicinity of the Enns River which could be crossed west of Hieflau. Following this there was to be an adjustment of the line of contact to conform to the southern border of the Austrian province of Oberdonau. This part of Austria in zone was to be occupied, organized and governed until taken over by the 15th Army Group. Thereafter, the Third Army would be prepared to leave for occupational purposes in Oberdonau in Austria, one infantry division and be ready to relieve Soviet forces remaining in the Austrian province. In addition, the Province of Salzburg in Austria was to be taken over if similar action had not been taken by the 15th Army Group.

On 23 May, the boundary between the Third and Seventh Armies was changed to give the Third control of areas as far south as the Italian border in a zone east of Innsbruck.

On 21 May, the 3rd Cavalry Group moved to Bad Aussee and on the following day, in the southern part of the XX Corps area, established contact with the 78th British Infantry Division at Tamsweg. On 23 May, the Group set up and later opened (29 May) its Command Post at Radstadt.