Coastal Redwood new growth yellowing at the tips

[BonsaiLoudon]

Hi all. I've had a new Coastal Redwood this year and it put on phenomenal growth. The new growth it put out in the fall was still light green 3 weeks ago (picture attached). Unfortunately, the tips turned yellow pretty suddenly. We've had a bit of a spurt of cold weather, it gets down to 20-30f each night, but the days are typically above freezing. In particular it was pretty rainy and cold the last few days. I've kept it watered, the soil is still moist from the rain, but I've been keeping it under burlap for wind protection and I have leaves piled up to the top of the pot for as much insulation as possible.

Any experience on how concerned I ought to be or what I can do?