Topband: EU frustration

[flood at ixi.net]

I turned a couple of insomnia-ridden nights into some careful listening on
topband.  I got to hear loads of stateside folks (including my neighbors
in WA, ID, MT, OR) dropping calls on DX stations I cannot hear - mostly EU
from what I gather from the posts.  I got no response from this question
last winter so I will ask again - can surrounding terrain mask or block
signals?  My path to EU is about 20 to 50 degrees azimuth, which has a
large mountain that blocks the sky up to 16 to 18 degrees above level
horizon.  Are EU signals arriving below this angle and blocked by the
mountain range?  I RX on a full-size dipole, K9AY, and a 1030-foot
beverage that slopes up that big mountain at about 16 degrees incline.

Any thoughts on the subject?  Thanks.

Steve - KK7UV