What does this traffic sign mean?

What does this sign mean?

• A

  Warning of dangerous areas with frequent lightning strikes.

• B

  Signal area where power lines cross above the road.

  According to National Technical Regulation on Road Signs QCVN 41:2019, the sign "overhead power cable" is denoted as W.239.
  In places where power lines cross above the road, sign W.239 must be placed and accompanied by sign W.509a "safe height" below.
  Sign W.239 is placed on the right side of the road for both directions, about 20 - 30m from the cable location.
  When the safety height is > 5.5m, it is not necessary to place sign W.239, except in cases where road sections have special operating requirements.

Japanese

Source: https://vtcnews.vn/bien-bao-giao-thong-nay-mang-y-nghia-gi-ar857949.html