The Syren Party disembarked at Murmansk on September 28, 1918. By this time, there was relatively little action on this front as both sides were looking ahead to the approach of winter. The Canadians spent the next several weeks becoming acclimatized to the region and then were sent south to the front line at Soroka. Once they arrived, Leckie received a promotion to full colonel and was given command of all troops at this forward position. The Canadians immediately began preparing for their stated role of training other Allied troops in the use of equipment for travelling overland under conditions of heavy snow. Major-General Maynard, however, was concerned by reports that the Bolsheviks were assembling military forces to the south and he decided to organize and equip a mobile force that could deal with any threat that might appear once the frigid winter settled in. The Canadians were naturally selected to be part of this force and formed what became known as the "Canadian "Malmoot" Company," named after a type of sled dog said to have a considerable strain of wolf in its genes. This company was divided into fifteen sections, each with one officer and five other ranks, and equipped with skis, snow shoes, toboggans and six sleds drawn by dogs.

In February as the temperatures dropped to the lowest in the winter, Major-General Maynard decided to launch a winter offensive to counter the growing Bolshevik strength. He decided that it was necessary to capture their main forward base, the town of Segeja south of Soroka. Colonel Leckie was given overall command of the operation. Leckie devised a somewhat complex plan, designed to achieve surprise, whereby several columns would set out at different times with their travel times calculated for them to reach their jumping-off positions and attack simultaneously on February 19, 1919. The attacking force was a mix of 600 British, French, Russian and Serbian troops, with Canadians represented in all columns. One column under Major John Eastham was to secure the left flank by capturing a village to the east; another column under Captain Adams would fight its way directly southwards along the railway; and a third column under Major Lawrence MacKenzie would take a circuitous route to the west over 110 kilometres ( 70 miles) of unmapped frozen forest and tundra to launch a surprise attack on the town itself. Despite the weather, described as "pitilessly cold, the temperature dropping to over 40 degrees below zero, with a biting wind and heavy snows squalls, " the attack was completely successful and a Bolshevik counter-attack by an armoured train was driven off. For their role in this attack, Majors MacKenzie and Eastham were awarded the Distinguished Service Order, Sergeant McNaughton received the Distinguished Conduct Medal and three other sergeants were promoted in the field to commissioned rank